Do not raise "inexact" from x86_64 SSE4.1 ceil, floor (bug 15479).

Do not raise "inexact" from x86_64 SSE4.1 ceil, floor (bug 15479).

Continuing fixes for ceil and floor functions not to raise the
"inexact" exception, this patch fixes the x86_64 SSE4.1 versions.  The
roundss / roundsd instructions take an immediate operand that
determines the rounding mode and whether to raise "inexact"; this just
needs bit 3 set to disable "inexact", which this patch does.

Remark: we don't have an SSE4.1 version of trunc / truncf (using this
instruction with operand 11); I'd expect one to make sense, but of
course it should be benchmarked against the existing C code.  I'll
file a bug in Bugzilla for the lack of such a version.

Tested for x86_64.

	[BZ #15479]
	* sysdeps/x86_64/fpu/multiarch/s_ceil.S (__ceil_sse41): Set bit 3
	of immediate operand to rounding instruction.
	* sysdeps/x86_64/fpu/multiarch/s_ceilf.S (__ceilf_sse41):
	Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_floor.S (__floor_sse41):
	Likewise.
	* sysdeps/x86_64/fpu/multiarch/s_floorf.S (__floorf_sse41):
	Likewise.