x86, relocs: Workaround for binutils 2.22.52.0.1 section bug

GNU ld 2.22.52.0.1 has a bug that it blindly changes symbols from
section-relative to absolute if they are in a section of zero length.
This turns the symbols __init_begin and __init_end into absolute
symbols.  Let the relocs program know that those should be treated as
relative symbols.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>

arch/x86/tools/relocs.c

@@ -56,7 +56,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  * as absolute (typically defined outside any section in the linker script.)
  */
 	[S_REL] =
-	"^_end$",
+	"^(__init_begin|__init_end|_end)$"
 };