MIPS: mistake in disassembling special privileged instruction (MFC)

[XVilka]

0xffffffff80affa10 03800c40 mfc0 t4, s0, 3
0xffffffff80affa14 80008c35 ori t4, t4, 0x80

In the disassemble result of the first instruction，mfc0 t4, s0, 3 ，s0 is a general register， but mfc0 is a privileged instruction.
For privileged instructions (mfc0 mtc0), the name should be indexed in Coprocessor 0 registers , not in general registers.

Originally was reported in radareorg/radare2#17372

@junchao-loongson might want to give a small reproducer with cstool, please give the offending bytes.