[RISCV] Remove reference to non-existant __builtin_riscv_sha512sum0l/__builtin_riscv_sha512sum1l.

This was a copy/paste mistake from sig0/sig1 which have high and low halves.
sum0 and sum1 have sum0r and sum1r instead.

Author: topperc

clang/lib/Headers/riscv_crypto.h

@@ -112,21 +112,11 @@ __riscv_sha512sig1l(uint32_t __x, uint32_t __y) {
   return __builtin_riscv_sha512sig1l(__x, __y);
 }
 
-static __inline__ uint32_t __attribute__((__always_inline__, __nodebug__))
-__riscv_sha512sum0l(uint32_t __x, uint32_t __y) {
-  return __builtin_riscv_sha512sum0l(__x, __y);
-}
-
 static __inline__ uint32_t __attribute__((__always_inline__, __nodebug__))
 __riscv_sha512sum0r(uint32_t __x, uint32_t __y) {
   return __builtin_riscv_sha512sum0r(__x, __y);
 }
 
-static __inline__ uint32_t __attribute__((__always_inline__, __nodebug__))
-__riscv_sha512sum1l(uint32_t __x, uint32_t __y) {
-  return __builtin_riscv_sha512sum1l(__x, __y);
-}
-
 static __inline__ uint32_t __attribute__((__always_inline__, __nodebug__))
 __riscv_sha512sum1r(uint32_t __x, uint32_t __y) {
   return __builtin_riscv_sha512sum1r(__x, __y);