[POWERPC] Fix for assembler -g

ppc64 does the unusual thing of using #include on a compiler-generated
assembly file (lparmap.s) from an assembly source file (head_64.S).
This runs afoul of my recent patch to pass -gdwarf2 to the assembler
under CONFIG_DEBUG_INFO.  This patch avoids the problem by disabling
DWARF generation (-g0) when producing lparmap.s.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kernel/Makefile

@@ -81,6 +81,7 @@ obj-y				+= iomap.o
 endif
 
 ifeq ($(CONFIG_PPC_ISERIES),y)
+CFLAGS_lparmap.s		+= -g0
 extra-y += lparmap.s
 $(obj)/head_64.o:	$(obj)/lparmap.s
 AFLAGS_head_64.o += -I$(obj)