MIPS: Make definitions of MIPSInst_FMA_{FUNC,FMTM} consistent with MIPS64 manual

The kernel definitions of MIPSInst_FMA_FUNC and MIPSInst_FMA_FFMT are not
consistent with MADD.fmt, NMADD.fmt and NMSUB.fmt in the MIPS64 manual [1],
the field func is bit 5..3 and fmt is bit 2..0, fix them. Otherwise there
exists error when add new instruction simulation.

[1] https://www.mips.com/?do-download=the-mips64-instruction-set-v6-06

Reported-by: Ming Wang <wangming01@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Author: seehearfeel

arch/mips/include/asm/inst.h

@@ -65,11 +65,11 @@
 #define I_FR_SFT	21
 #define MIPSInst_FR(x) ((MIPSInst(x) & 0x03e00000) >> I_FR_SFT)
 
-#define I_FMA_FUNC_SFT	2
-#define MIPSInst_FMA_FUNC(x) ((MIPSInst(x) & 0x0000003c) >> I_FMA_FUNC_SFT)
+#define I_FMA_FUNC_SFT	3
+#define MIPSInst_FMA_FUNC(x) ((MIPSInst(x) & 0x00000038) >> I_FMA_FUNC_SFT)
 
 #define I_FMA_FFMT_SFT	0
-#define MIPSInst_FMA_FFMT(x) (MIPSInst(x) & 0x00000003)
+#define MIPSInst_FMA_FFMT(x) (MIPSInst(x) & 0x00000007)
 
 typedef unsigned int mips_instruction;