arm: enable Cortex-R52+ CPU

Patch is adding Cortex-R52+ as 'cortex-r52plus' command line
flag for -mcpu option.

bfd/

	* cpu-arm.c: New Cortex-R52+ CPU.

gas/

	* NEWS: Update docs.
	* config/tc-arm.c: New Cortex-R52+ CPU.
	* doc/c-arm.texi: Update docs.
	* testsuite/gas/arm/cpu-cortex-r52plus.d: New test.
5 files changed