powerpc/boot: allow wrapper to work on non-english system

if the language is not english objdump output is not parsed correctly
and format is "". Later, "ld -m $format" fails.

This patch adds "LANG=C" to force english output for objdump.
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/boot/wrapper

@@ -154,7 +154,7 @@ if [ -z "$kernel" ]; then
     kernel=vmlinux
 fi
 
-elfformat="`${CROSS}objdump -p "$kernel" | grep 'file format' | awk '{print $4}'`"
+LANG=C elfformat="`${CROSS}objdump -p "$kernel" | grep 'file format' | awk '{print $4}'`"
 case "$elfformat" in
     elf64-powerpcle)	format=elf64lppc	;;
     elf64-powerpc)	format=elf32ppc	;;