[llvm-readobj] Remove legacy GNU_PROPERTY_X86_ISA_1_{NEEDED,USED} and dump new...

[llvm-readobj] Remove legacy GNU_PROPERTY_X86_ISA_1_{NEEDED,USED} and dump new GNU_PROPERTY_X86_ISA_1_{NEEDED,USED}

https://sourceware.org/bugzilla/show_bug.cgi?id=26703 deprecated the
previous GNU_PROPERTY_X86_ISA_1_{CMOV,SSE,*} values (renamed to `COMPAT`)
and added new values.

Since the legacy values are not used by compilers, having dumping support in
llvm-readobj is unnecessary. So just drop the legacy feature.

The new values are used by GCC 11
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97250) `-march=x86-64-v[234]` to
indicate the micro-architecture ISA levels.

Differential Revision: https://reviews.llvm.org/D98818