pwm: Changes to PWM driver for the PCA9685.
pwm: Changes to PWM driver for the PCA9685.

- Changed behavior of duty cycle to have the signal ON time as the
  duty percentage instead off the off time. Note however, this requires
  that the off time is controlled. The behavior seems to be inverse of
  what the user will expect on the header IO.

Change-Id: I1e7abf0324509de375d545a0215fd1edf2283814
Work-by: Johan Kruger <fcf90dfa9fa724475d3fb68816bd1293fa6e6084@windriver.com>
Signed-off-by: Peter Mitsis <22bf95476f8cdbda3c8a9a9bf1bdda876f69ea7a@windriver.com>

bigdinotech/zephyr,nashif/zephyr,kraj/zephyr,aceofall/zephyr-iotos,explora26/zephyr,zephyrproject-rtos/zephyr,jamesonwilliams/zephyr-kernel,mbolivar/zephyr,32bitmicro/zephyr,runchip/zephyr-cc3220,jamesonwilliams/zephyr-kernel,explora26/zephyr,fractalclone/zephyr-riscv,fbsder/zephyr,sharronliu/zephyr,runchip/zephyr-cc3200,zephyriot/zephyr,nashif/zephyr,galak/zephyr,explora26/zephyr,mirzak/zephyr-os,zephyriot/zephyr,ldts/zephyr,runchip/zephyr-cc3200,aceofall/zephyr-iotos,explora26/zephyr,jamesonwilliams/zephyr-kernel,zephyriot/zephyr,erwango/zephyr,bboozzoo/zephyr,finikorg/zephyr,bboozzoo/zephyr,pklazy/zephyr,fractalclone/zephyr-riscv,bboozzoo/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,aceofall/zephyr-iotos,fractalclone/zephyr-riscv,Vudentz/zephyr,zephyriot/zephyr,tidyjiang8/zephyr-doc,bigdinotech/zephyr,pklazy/zephyr,erwango/zephyr,ldts/zephyr,ldts/zephyr,punitvara/zephyr,mbolivar/zephyr,kraj/zephyr,tidyjiang8/zephyr-doc,bigdinotech/zephyr,runchip/zephyr-cc3200,rsalveti/zephyr,punitvara/zephyr,runchip/zephyr-cc3220,sharronliu/zephyr,sharronliu/zephyr,bigdinotech/zephyr,galak/zephyr,fbsder/zephyr,coldnew/zephyr-project-fork,finikorg/zephyr,holtmann/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,kraj/zephyr,coldnew/zephyr-project-fork,fbsder/zephyr,Vudentz/zephyr,holtmann/zephyr,bboozzoo/zephyr,aceofall/zephyr-iotos,fbsder/zephyr,tidyjiang8/zephyr-doc,bboozzoo/zephyr,zephyriot/zephyr,erwango/zephyr,Vudentz/zephyr,pklazy/zephyr,rsalveti/zephyr,coldnew/zephyr-project-fork,32bitmicro/zephyr,32bitmicro/zephyr,aceofall/zephyr-iotos,sharronliu/zephyr,finikorg/zephyr,rsalveti/zephyr,ldts/zephyr,sharronliu/zephyr,mirzak/zephyr-os,runchip/zephyr-cc3220,zephyrproject-rtos/zephyr,tidyjiang8/zephyr-doc,pklazy/zephyr,jamesonwilliams/zephyr-kernel,32bitmicro/zephyr,Vudentz/zephyr,coldnew/zephyr-project-fork,GiulianoFranchetto/zephyr,rsalveti/zephyr,mirzak/zephyr-os,ldts/zephyr,kraj/zephyr,runchip/zephyr-cc3220,fractalclone/zephyr-riscv,punitvara/zephyr,runchip/zephyr-cc3220,zephyrproject-rtos/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,erwango/zephyr,mirzak/zephyr-os,runchip/zephyr-cc3200,finikorg/zephyr,punitvara/zephyr,mirzak/zephyr-os,explora26/zephyr,holtmann/zephyr,galak/zephyr,mbolivar/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,fbsder/zephyr,fractalclone/zephyr-riscv,jamesonwilliams/zephyr-kernel,erwango/zephyr,pklazy/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,coldnew/zephyr-project-fork,galak/zephyr,32bitmicro/zephyr,runchip/zephyr-cc3200,rsalveti/zephyr,galak/zephyr,nashif/zephyr,tidyjiang8/zephyr-doc,holtmann/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,holtmann/zephyr,bigdinotech/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr