arch: arm: conditionally select FP extension in cortex-m MCUs
arch: arm: conditionally select FP extension in cortex-m MCUs

This commit conditionally selects the ARMV7_M_ARMV8_M_FP option
in ARMv7-M/ARMv8-M Mainline processors, when the Floating Point
Extension is implemented (CPU_HAS_FPU is selected).

Signed-off-by: Ioannis Glaropoulos <5921cc8bab7e1d4329f52fd8f6268f9692e3de80@nordicsemi.no>

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