CMSIS/RTX: Patch RTX4 to preserve osThreadDef compatibility
CMSIS/RTX: Patch RTX4 to preserve osThreadDef compatibility

mbed OS used older RTX4 version and with osThreadDef accepting only 3
parameters, to preserve compatibility we hardcode the 'instances'
parameter to 1.

(cherry picked from commit 428acae1b2ac15c3ad523e8d40755a9301220822)
(cherry picked from commit 4360b7bbf815c4d812005938c9c27af199803a97)

andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,mbedmicro/mbed