objtool: Disable GCC '-Wpacked' warnings

Objtool is failing to build with GCC 4.4.7 due to the following
warnings:

cc1: warnings being treated as errors
In file included from orc.h:21,
from orc_gen.c:21:
orc_types.h:86: error: packed attribute is unnecessary for ‘sp_offset’
orc_types.h:87: error: packed attribute is unnecessary for ‘bp_offset’
orc_types.h:88: error: packed attribute is unnecessary for ‘sp_reg’

I suspect those warnings are a GCC bug. But -Wpacked isn't very useful
anyway, so just disable it.

Signed-off-by: Josh Poimboeuf <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

tools/objtool/Makefile

···
 all: $(OBJTOOL)
 
 INCLUDES := -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi
-CFLAGS   += -Wall -Werror $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -fomit-frame-pointer -O2 -g $(INCLUDES)
+WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
+CFLAGS   += -Wall -Werror $(WARNINGS) -fomit-frame-pointer -O2 -g $(INCLUDES)
 LDFLAGS  += -lelf $(LIBSUBCMD)
 
 # Allow old libelf to be used: