nouveau: nak: fix wrong opcode in frnd
The order of the opcodes is wrong. Opcode 0x113 is used when both source and destination are F64, and 0x107 otherwise. This can be cross-checked with the GV100 emitter in NV50.
In fact, this mistake makes nvdisasm abort with the error:
nvdisasm error: Unrecognized operation for functional unit 'uC'
Fix it by inverting the logic for the opcode selection.