x86_64: Exclude SSE, AVX and FMA4 variants in libm multiarch

When glibc is built with ISA level 3 or higher by default, the resulting
glibc binaries won't run on SSE or FMA4 processors.  Exclude SSE, AVX and
FMA4 variants in libm multiarch when ISA level 3 or higher is enabled by
default.

When glibc is built with ISA level 2 enabled by default, only keep SSE4.1
variant.

Fixes BZ 31335.

NB: elf/tst-valgrind-smoke test fails with ISA level 4, because valgrind
doesn't support AVX512 instructions:

https://bugs.kde.org/show_bug.cgi?id=383010



Reviewed-by: H.J. Lu <hjl.tools@gmail.com>