bpfilter: fix build error

bpfilter Makefile assumes that the system locale is en_US, and the
parsing of objdump output fails.
Set LC_ALL=C and, while at it, rewrite the objdump parsing so it spawns
only 2 processes instead of 7.

Fixes: d2ba09c17a064 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bpfilter/Makefile

@@ -21,8 +21,10 @@ endif
 # which bpfilter_kern.c passes further into umh blob loader at run-time
 quiet_cmd_copy_umh = GEN $@
       cmd_copy_umh = echo ':' > $(obj)/.bpfilter_umh.o.cmd; \
-      $(OBJCOPY) -I binary -O `$(OBJDUMP) -f $<|grep format|cut -d' ' -f8` \
-      -B `$(OBJDUMP) -f $<|grep architecture|cut -d, -f1|cut -d' ' -f2` \
+      $(OBJCOPY) -I binary \
+          `LC_ALL=C objdump -f net/bpfilter/bpfilter_umh \
+          |awk -F' |,' '/file format/{print "-O",$$NF} \
+          /^architecture:/{print "-B",$$2}'` \
       --rename-section .data=.init.rodata $< $@
 
 $(obj)/bpfilter_umh.o: $(obj)/bpfilter_umh