intel: enable -mfpmath=sse on x86

It's not enabled by default until `-msse2` and -ffast-math is passed.
We pass only the `-msse2`. Let's align it with main `meson.build`.

See: https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html (-mfpmath).

Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21371>

src/intel/meson.build

@@ -21,7 +21,7 @@
 c_sse2_args = []
 c_sse2_arg = []
 if ['x86', 'x86_64'].contains(host_machine.cpu_family())
-  c_sse2_arg = ['-msse2']
+  c_sse2_arg = ['-msse2', '-mfpmath=sse']
   c_sse2_args = [c_sse2_arg, '-mstackrealign']
 endif
 inc_intel = include_directories('.')