[ELF] Remove a R_ARM_PCA special case from relocateNonAlloc

https://reviews.llvm.org/D75042 added a special case about R_ARM_PCA to
relocateNonAlloc. This is untested and actually unused in the wild.

Author: MaskRay

lld/ELF/InputSection.cpp

@@ -975,7 +975,7 @@ void InputSection::relocateNonAlloc(uint8_t *buf, ArrayRef<RelTy> rels) {
     std::string msg = getLocation(offset) + ": has non-ABS relocation " +
                       toString(type) + " against symbol '" + toString(sym) +
                       "'";
-    if (expr != R_PC && expr != R_ARM_PCA) {
+    if (expr != R_PC) {
       error(msg);
       return;
     }