[ARM] Fix VMOVSR pattern requirements

The required target features for VMOVSR instruction (integer -> MVE
FP register copy) are HasFPRegs and UseVMOVSR (see
https://reviews.llvm.org/D60694).

The instruction selection pattern must use the same set of
requirements (i.e., HasFPRegs instead of HasVFP2). The discrepancy
can cause instruction selection failure when compiling code for
execute-only position-independence mode.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D147523