kexec_file: Drop pr_err in weak implementations of arch_kexec_apply_relocations[_add]

kexec_load_purgatory() can fail for many reasons - there is no need to
print an error when encountering unsupported relocations.

This solves a build issue on powerpc with binutils v2.36 and newer [1],
and likely also with the clang integrated assembler [2].

Since commit d1bcae833b32f1 ("ELF: Don't generate unused section
symbols") [3], binutils started dropping section symbols that it thought
were unused.  This isn't an issue in general, but with kexec_file.c, gcc
is placing kexec_arch_apply_relocations[_add] into a separate
.text.unlikely section and the section symbol ".text.unlikely" is being
dropped. Due to this, recordmcount is unable to find a non-weak symbol
in .text.unlikely to generate a relocation record against. Dropping
pr_err() calls results in these functions being left in .text section,
enabling recordmcount to emit a proper relocation record.

[1] linuxppc/issues#388
[2] ClangBuiltLinux#981
[3] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1

Signed-off-by: Naveen N. Rao <[email protected]>

Author: rnav

kernel/kexec_file.c

@@ -121,7 +121,6 @@ int __weak
 arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
 				 const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 {
-	pr_err("RELA relocation unsupported.\n");
 	return -ENOEXEC;
 }
 
@@ -138,7 +137,6 @@ int __weak
 arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
 			     const Elf_Shdr *relsec, const Elf_Shdr *symtab)
 {
-	pr_err("REL relocation unsupported.\n");
 	return -ENOEXEC;
 }