Correct options in GCC manual.

	* doc/invoke.texi (Option Summary, ARC Options): Remove -mcrc,
	-mold-di-patterns, -mCPU=A5, -mA5. Add -mforce-short, -mlra,
	-mlra-priority-compact, -mlra-priority-noncompact,
	-mlra-priority-none and -mucb-count. Replace -mcpu=ARCv2EM by
	-mcpu=ARCEM and add -mAEM and -mARCEM as synonyms. Mark
	-mbarrel_shifter, -mdiv_rem, -mdpfp_compact, -mdpfp_fast,
	-mdsp_packa, -mmac_24, -mmac_d16, -mmpy_option, -mspfp_compact,
	-mspfp_fast and -mcode_density as deprecated and replace by
	equivalents without '_'. Partition options into groups are reorder
	alphabetically in groups. Update summary to match detailed list.