Remove duplicated -Werror in dtc Makefile

The "-Werror" compiler flag is currently declared twice in the
Makefile, one time in WARNINGS, and one time in CFLAGS. Let's
remove one of them.

Signed-off-by: Thomas Huth <thuth@redhat.com>
[Moved remaining -Werror from WARNINGS to CFLAGS --dwg]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Makefile

@@ -16,7 +16,7 @@ LOCAL_VERSION =
 CONFIG_LOCALVERSION =
 
 CPPFLAGS = -I libfdt -I .
-WARNINGS = -Werror -Wall -Wpointer-arith -Wcast-qual -Wnested-externs \
+WARNINGS = -Wall -Wpointer-arith -Wcast-qual -Wnested-externs \
 	-Wstrict-prototypes -Wmissing-prototypes -Wredundant-decls -Wshadow
 CFLAGS = -g -Os -fPIC -Werror $(WARNINGS)