Fix low reg issue in Thumb-2 movsi patterns

Fix low reg issue in Thumb-2 movsi patterns

The Thumb-2 movsi patterns try to prefer low registers for loads and stores.
However this is done incorrectly by using 2 separate variants with 'l' and 'h'
register classes.  The register allocator will only use low registers, and
as a result we end up with significantly more spills and moves to high
registers.  Fix this by merging the alternatives and use 'l*r' to indicate
preference for low registers.  This saves ~400 instructions from the pr77308
testcase.

    gcc/
	* config/arm/thumb2.md (thumb2_movsi_insn): Fix load/store low reg.
	* config/arm/vfp.md (thumb2_movsi_vfp): Likewise.

From-SVN: r273802