[RISCV] Don't make it an error have Zve* and V at the same time.

[craig.topper]

Summary

This should not be an error. V is a valid implementation of Zve.

Spec clarified here
https://github.com/riscv/riscv-v-spec/commit/9a877e8553362ff03a9b22b98e321b59aff50398

[kito-cheng]

LGTM

llvm/lib/Support/RISCVISAInfo.cpp

return createStringError(
         errc::invalid_argument,
         "zve64d requires d extension to also be specified");
 
   if (HasZvl && !HasVector)
     return createStringError(
         errc::invalid_argument,
         "zvl*b requires v or zve* extension to also be specified");
 
-  // Could not implement Zve* extension and the V extension at the same time.
-  if (HasZve32x && HasV)
-    return createStringError(
-        errc::invalid_argument,
-        "It is illegal to specify the v extension with zve* extensions");
-
   // Additional dependency checks.
   // TODO: The 'q' extension requires rv64.
   // TODO: It is illegal to specify 'e' extensions with 'f' and 'd'.
 
   return Error::success();
 }
 
 static const char *ImpliedExtsV[] = {"zvl128b", "f", "d"};