Align stack to 16 bytes when calling __errno_location

We should align stack to 16 bytes when calling __errno_location.

	[BZ #18661]
	* sysdeps/x86_64/fpu/s_cosf.S (__cosf): Align stack to 16 bytes
	when calling __errno_location.
	* sysdeps/x86_64/fpu/s_sincosf.S (__sincosf): Likewise.
	* sysdeps/x86_64/fpu/s_sinf.S (__sinf): Likewise.