objtool: Fix compile failure when using the x32 compiler

When compiling the v6.9-rc1 kernel with the x32 compiler, the following
errors are reported. The reason is that we take an "unsigned long"
variable and print it using "PRIx64" format string.

	In file included from check.c:16:
	check.c: In function ‘add_dead_ends’:
	/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:46:17: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 5 has type ‘long unsigned int’ [-Werror=format=]
	   46 |                 "%s: warning: objtool: " format "\n",   \
	      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
	check.c:613:33: note: in expansion of macro ‘WARN’
	  613 |                                 WARN("can't find unreachable insn at %s+0x%" PRIx64,
	      |                                 ^~~~
	...

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org