libc: printf: Add support for 'z' length specifier
libc: printf: Add support for 'z' length specifier

The 'z' length specifier is the appropriate one to be used with size_t
(%zu) and ssize_t (%zd) types. Having support for this in our libc
means that we can utilize the compiler format string checks
(__printf_like) without getting warnings of incorrect format
specifiers for size_t and ssize_t variables.

Change-Id: I73fec0145692e0a59934cab548caf24c1c16a3df
Signed-off-by: Johan Hedberg <628991c7b0a19c384f9b99c21ec330ce952bb838@intel.com>

galak/zephyr,aceofall/zephyr-iotos,runchip/zephyr-cc3200,fbsder/zephyr,nashif/zephyr,fbsder/zephyr,rsalveti/zephyr,aceofall/zephyr-iotos,GiulianoFranchetto/zephyr,bboozzoo/zephyr,erwango/zephyr,runchip/zephyr-cc3220,GiulianoFranchetto/zephyr,erwango/zephyr,tidyjiang8/zephyr-doc,tidyjiang8/zephyr-doc,finikorg/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,kraj/zephyr,explora26/zephyr,sharronliu/zephyr,punitvara/zephyr,finikorg/zephyr,nashif/zephyr,ldts/zephyr,runchip/zephyr-cc3200,explora26/zephyr,galak/zephyr,ldts/zephyr,holtmann/zephyr,aceofall/zephyr-iotos,zephyrproject-rtos/zephyr,runchip/zephyr-cc3220,bigdinotech/zephyr,runchip/zephyr-cc3200,tidyjiang8/zephyr-doc,pklazy/zephyr,mbolivar/zephyr,ldts/zephyr,punitvara/zephyr,sharronliu/zephyr,fractalclone/zephyr-riscv,bboozzoo/zephyr,GiulianoFranchetto/zephyr,fractalclone/zephyr-riscv,runchip/zephyr-cc3220,kraj/zephyr,bigdinotech/zephyr,pklazy/zephyr,rsalveti/zephyr,GiulianoFranchetto/zephyr,aceofall/zephyr-iotos,kraj/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,rsalveti/zephyr,nashif/zephyr,Vudentz/zephyr,tidyjiang8/zephyr-doc,zephyriot/zephyr,mbolivar/zephyr,finikorg/zephyr,galak/zephyr,explora26/zephyr,Vudentz/zephyr,zephyriot/zephyr,zephyrproject-rtos/zephyr,fbsder/zephyr,fbsder/zephyr,sharronliu/zephyr,mbolivar/zephyr,explora26/zephyr,kraj/zephyr,rsalveti/zephyr,aceofall/zephyr-iotos,tidyjiang8/zephyr-doc,pklazy/zephyr,GiulianoFranchetto/zephyr,sharronliu/zephyr,galak/zephyr,kraj/zephyr,zephyriot/zephyr,bboozzoo/zephyr,fractalclone/zephyr-riscv,zephyriot/zephyr,rsalveti/zephyr,punitvara/zephyr,fractalclone/zephyr-riscv,holtmann/zephyr,mbolivar/zephyr,runchip/zephyr-cc3220,bigdinotech/zephyr,holtmann/zephyr,ldts/zephyr,zephyriot/zephyr,explora26/zephyr,runchip/zephyr-cc3200,sharronliu/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,fractalclone/zephyr-riscv,fbsder/zephyr,runchip/zephyr-cc3200,bboozzoo/zephyr,ldts/zephyr,Vudentz/zephyr,galak/zephyr,Vudentz/zephyr,runchip/zephyr-cc3220,finikorg/zephyr,bboozzoo/zephyr,erwango/zephyr,holtmann/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,pklazy/zephyr,punitvara/zephyr,holtmann/zephyr,nashif/zephyr,erwango/zephyr,erwango/zephyr,pklazy/zephyr,punitvara/zephyr