[MIPS] PR gas/14798: Limit IRIX5 specific default typing to IRIX targets

[MIPS] PR gas/14798: Limit IRIX5 specific default typing to IRIX targets

On IRIX 5, every global symbol that is not explicitly labelled as
being a function is assumed to be an object.  There is no reason
why IRIX behaviour should extend to all MIPS targets, so limit this
to only IRIX targets.

gas/
	PR 14798
	* config/tc-mips.c (s_mips_globl): Only treat symbols that are
	not explicitly labelled as BSF_OBJECTs for IRIX targets.
	* testsuite/gas/mips/pr14798.s: New test source.
	* testsuite/gas/mips/pr14798-irix.d: New test.
	* testsuite/gas/mips/pr14798.d: Likewise.
	* testsuite/gas/mips/mips.exp: Run the new tests.

binutils/
	PR 14798
	* testsuite/binutils-all/readelf.ss-mips: Update reference output.
	* testsuite/binutils-all/readelf.ss-tmips: Likewise.

ld/
	PR 14798
	* testsuite/ld-mips-elf/reloc-6a.s: Specify .text section for
	global code symbols.
	* testsuite/ld-mips-elf/reloc-6b.s: Likewise.