[ELF] Delete the RelExpr member R_HINT. NFC

R_HINT is ignored like R_NONE. There are no strong reasons to keep
R_HINT. The largest RelExpr member R_RISCV_PC_INDIRECT is 60 now.

Differential Revision: https://reviews.llvm.org/D71822

lld/ELF/Arch/ARM.cpp

@@ -140,7 +140,7 @@ RelExpr ARM::getRelExpr(RelType type, const Symbol &s,
     // given address. It can be used to implement a special linker mode which
     // rewrites ARMv4T inputs to ARMv4. Since we support only ARMv4 input and
     // not ARMv4 output, we can just ignore it.
-    return R_HINT;
+    return R_NONE;
   default:
     return R_ABS;
   }

lld/ELF/Relocations.cpp

@@ -1250,8 +1250,8 @@ static void scanReloc(InputSectionBase &sec, OffsetGetter &getOffset, RelTy *&i,
   const uint8_t *relocatedAddr = sec.data().begin() + rel.r_offset;
   RelExpr expr = target->getRelExpr(type, sym, relocatedAddr);
 
-  // Ignore "hint" relocations because they are only markers for relaxation.
-  if (oneof<R_HINT, R_NONE>(expr))
+  // Ignore R_*_NONE and other marker relocations.
+  if (expr == R_NONE)
     return;
 
   // We can separate the small code model relocations into 2 categories:

lld/ELF/Relocations.h

@@ -40,7 +40,6 @@ enum RelExpr {
   R_GOTPLT,
   R_GOTPLTREL,
   R_GOTREL,
-  R_HINT,
   R_NEG_TLS,
   R_NONE,
   R_PC,