The Move to Vector Status and Control Register (mtvscr) instruction
uses VRB as the source register. Fix the code generator to correctly
decode the VRB field. That is, use "rB(ctx->opcode)" instead of
"rD(ctx->opcode)".
Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>