[Hexagon] Handle operand type differences for A2_tfrpi

The instruction A2_tfrpi has a 64-bit operand, while the corresponding
intrinsic takes a 32-bit value. The actual value has only 8 significant
bits, so the difference is only in the type used to represent it.
In order to map the intrinsic to the instruction, the operand needs to
be extended to the correct type.

llvm-svn: 268635