MIPS/BFD: Correct microMIPS cross-mode BAL to JALX relaxation

MIPS/BFD: Correct microMIPS cross-mode BAL to JALX relaxation

Fix a bug in commit a6ebf6169a1b ("MIPS: Convert cross-mode BAL to
JALX") and in BFD linker relaxation correct the microMIPS interpretation
of the branch offset, which is supposed to be shifted by 1 bit, rather
than 2 as in the regular MIPS case.

	bfd/
	* elfxx-mips.c (mips_elf_perform_relocation): Correct microMIPS
	branch offset interpretation.

	gas/
	* testsuite/gas/mips/branch-addend-micromips.d: New test.
	* testsuite/gas/mips/branch-addend-micromips-n32.d: New test.
	* testsuite/gas/mips/branch-addend-micromips-n64.d: New test.
	* testsuite/gas/mips/branch-addend-micromips.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.

	ld/
	* testsuite/ld-mips-elf/bal-jalx-addend-micromips.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-addend-micromips-n32.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-addend-micromips-n64.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-local-micromips.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-local-micromips-n32.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-local-micromips-n64.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-pic-micromips.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic-micromips-n32.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic-micromips-n64.d: New test.
	* testsuite/ld-mips-elf/bal-jalx-pic-ignore-micromips.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-pic-ignore-micromips-n32.d: New
	test.
	* testsuite/ld-mips-elf/bal-jalx-pic-ignore-micromips-n64.d: New
	test.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.