optionrom: create .PHONY variable

Signed-off-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

pc-bios/optionrom/Makefile

@@ -6,6 +6,7 @@ include ../../config-host.mak
 include $(SRC_PATH)/rules.mak
 
 VPATH=$(SRC_PATH)/pc-bios/optionrom
+.PHONY : all clean build-all
 
 CFLAGS := -Wall -Wstrict-prototypes -Werror -fomit-frame-pointer -fno-builtin
 CFLAGS += -I$(SRC_PATH)