kernel: pthread: correcting pthread_setschedparam.
kernel: pthread: correcting pthread_setschedparam.

pthread_setschedparam() uses k_thread_priority_set()
to set pthread priority. There is an error in argument
in k_thread_priority_seti() due to which system correct
priority was not set. Correcting this error.

Signed-off-by: Youvedeep Singh <7f33386d52951c3e7a699b9509267436d9be79f8@intel.com>

nashif/zephyr,Vudentz/zephyr,galak/zephyr,galak/zephyr,kraj/zephyr,finikorg/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,explora26/zephyr,mbolivar/zephyr,galak/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,punitvara/zephyr,mbolivar/zephyr,galak/zephyr,mbolivar/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,Vudentz/zephyr,finikorg/zephyr,punitvara/zephyr,finikorg/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,punitvara/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,explora26/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,nashif/zephyr,finikorg/zephyr,explora26/zephyr,ldts/zephyr,Vudentz/zephyr,ldts/zephyr,finikorg/zephyr,kraj/zephyr,mbolivar/zephyr,mbolivar/zephyr,zephyriot/zephyr,kraj/zephyr,punitvara/zephyr,zephyriot/zephyr,ldts/zephyr,zephyriot/zephyr,Vudentz/zephyr,explora26/zephyr