Minor SPARC T4 and M7 fixes and additions.

	* config/sparc/sparc.c (sparc_option_override): Set function
	alignment for -mcpu=niagara7 to 64 to match the I$ line.
	* config/sparc/sparc.h (BRANCH_COST): Set the SPARC M7 branch
	latency to 1.
	* config/sparc/sparc.h (BRANCH_COST): Set the SPARC T4 branch
	latency to 2.
	* config/sparc/sol2.h: Fix a ASM_CPU32_DEFAULT_SPEC typo.
	* gcc.target/sparc/niagara7-align.c: New test.

From-SVN: r248184