[PATCH, GCC/ARM, 10/10] Enable -mcmse

[PATCH, GCC/ARM, 10/10] Enable -mcmse

The patch is straightforward: it redefines ARMv8_1m_main as having the
same features as ARMv8m_main (and thus as having the cmse feature) with
the extra features represented by armv8_1m_main.  It also removes the
error for using -mcmse on Armv8.1-M Mainline.

*** gcc/ChangeLog ***

2020-01-16  Mihail-Calin Ionescu  <mihail.ionescu@arm.com>
2020-01-16  Thomas Preud'homme  <thomas.preudhomme@arm.com>

	* config/arm/arm-cpus.in (ARMv8_1m_main): Redefine as an extension to
	Armv8-M Mainline.
	* config/arm/arm.c (arm_options_perform_arch_sanity_checks): Remove
	error for using -mcmse when targeting Armv8.1-M Mainline.