[RISCV][NFC] Use TargetRegisterClass::hasSubClassEq in storeRegToStackSlot/loadReadFromStackSlot

Simply checking for register class equality will break once additional 
register classes are added (as is done for the RVC instruction set extension).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320036 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed