[RISCV] Add AltFmtType = IS_NOT_ALTFMT to SF_VFNRCLIP_X(U)_F_QF. (#164759)

These instructions are FP instructions with SEW=8. vtype.altfmt=1 should
be considered reserved for them.

Author: topperc

llvm/lib/Target/RISCV/RISCVInstrInfoXSf.td

@@ -482,7 +482,7 @@ let Predicates = [HasVendorXSfvfwmaccqqq] in {
   defm SF_VFWMACC_4x4x4 : VPseudoSiFiveVFWMACC;
 }
 
-let Predicates = [HasVendorXSfvfnrclipxfqf] in {
+let Predicates = [HasVendorXSfvfnrclipxfqf], AltFmtType = IS_NOT_ALTFMT in {
   defm SF_VFNRCLIP_XU_F_QF : VPseudoSiFiveVFNRCLIP;
   defm SF_VFNRCLIP_X_F_QF : VPseudoSiFiveVFNRCLIP;
 }