modsign: lookup lines ending in .ko in .mod files

This does the same as commit ef591a55 (scripts/Makefile.modpost: error
in finding modules from .mod files), but for scripts/Makefile.modsign

Maybe we should also apply to Makefile.modsign and Makefile.modinst
the change applied to Makefile.modpost by commit ea4054a2 (modpost:
handle huge numbers of modules) ?
Reviewed-by: NWilly Tarreau <w@1wt.eu>
Signed-off-by: NBertrand Jacquin <beber@meleeweb.net>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

scripts/Makefile.modsign

@@ -7,7 +7,7 @@ __modsign:
 
 include scripts/Kbuild.include
 
-__modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
+__modules := $(sort $(shell grep -h '\.ko$$' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
 modules := $(patsubst %.o,%.ko,$(wildcard $(__modules:.ko=.o)))
 
 PHONY += $(modules)