[FMV] Allow mixing target_version with target_clones. (#86493)

The latest ACLE allows it and further clarifies the following
in regards to the combination of the two attributes:

"If the `default` matches with another explicitly provided
 version in the same translation unit, then the compiler can
 emit only one function instead of the two. The explicitly
 provided version shall be preferred."

("default" refers to the default clone here)

https://github.com/ARM-software/acle/pull/310