kernel/arch/m33: Add PSPLIM support
kernel/arch/m33: Add PSPLIM support

This adds support for hardware stack limiter available in ARMv8-M. On
each context switch PSPLIM register is updated with a stack limit
address for current stack. Hard fault is triggered once stack pointer
(PSP) is decreased past this limit with PC set to instruction which
modified stack and 20th bit set in CFSR register to indicate stack
overflow.

mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core