[Driver][ARM] Disable unsupported features when nofp arch extension is used

A list of target features is disabled when there is no hardware
floating-point support. This is the case when one of the following
options is passed to clang:

 - -mfloat-abi=soft
 - -mfpu=none

This option list is missing, however, the extension "+nofp" that can be
specified in -march flags, such as "-march=armv8-a+nofp".

This patch also disables unsupported target features when nofp is passed
to -march.

Differential Revision: https://reviews.llvm.org/D82948