Add missing ARMv8-M special registers

Add missing ARMv8-M special registers

2016-08-26  Thomas Preud'homme  <thomas.preudhomme@arm.com>

gas/
	* config/tc-arm.c (v7m_psrs): Add MSPLIM, PSPLIM, MSPLIM_NS,
	PSPLIM_NS, PRIMASK_NS, BASEPRI_NS, FAULTMASK_NS, CONTROL_NS, SP_NS and
	their lowecase counterpart special registers.  Write register
	identifier in hex.
	* testsuite/gas/arm/archv8m-cmse-msr.s: Reorganize tests per
	operation, special register and then case.  Use different register for
	each operation.  Add tests for new special registers.
	* testsuite/gas/arm/archv8m-cmse-msr-base.d: Adapt expected result
	accordingly.
	* testsuite/gas/arm/archv8m-cmse-msr-main.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-4.d: Likewise.

opcodes/
	* arm-dis.c (psr_name): Use hex as case labels.  Add detection for
	MSPLIM, PSPLIM, MSPLIM_NS, PSPLIM_NS, PRIMASK_NS, BASEPRI_NS,
	FAULTMASK_NS, CONTROL_NS and SP_NS special registers.