Add CLI support for the mve architecture extensions.

Is this OK for trunk?

Cheers,
Andre

bfd/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* elf32-arm.c (elf32_arm_merge_eabi_attributes): Add case
         for Tag_MVE_arch

binutils/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* readelf.c (arm_attr_tag_MVE_arch): New array for Tag_MVE_arch
         values.
         (arm_attr_public_tag arm_attr_public_tags): Add case for
         Tag_MVE_arch

elfcpp/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* arm.h (Tag_MVE_arch): Define new enum value.

gas/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* config/tc-arm.c (mve_ext, mve_fp_ext): New features.
         (armv8_1m_main_ext_table): Add new extensions.
         (aeabi_set_public_attributes): Translate new features to
         new build attributes.
         (arm_convert_symbolic_attribute): Add Tag_MVE_arch.

         * doc/c-arm.texi: Document new extensions and new build attribute.

include/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* elf/arm.h (Tag_MVE_arch): Define new enum value.
	* opcode/arm.h (FPU_MVE, FPU_MVE_FP): New MACROs
         for new features.