[media] atomisp: use correct dialect to disable warnings

There's a Macro that checks if gcc supports a warning before
disabling it. Use it, in order to avoid warnings when building
with older gcc versions.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/atomisp/i2c/Makefile

@@ -21,5 +21,7 @@ obj-$(CONFIG_VIDEO_LM3554) += lm3554.o
 
 # HACK! While this driver is in bad shape, don't enable several warnings
 #       that would be otherwise enabled with W=1
-ccflags-y += -Wno-unused-but-set-variable -Wno-missing-prototypes \
-	     -Wno-unused-const-variable -Wno-missing-declarations
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+ccflags-y += $(call cc-disable-warning, unused-const-variable)
+ccflags-y += $(call cc-disable-warning, missing-prototypes)
+ccflags-y += $(call cc-disable-warning, missing-declarations)

drivers/staging/media/atomisp/i2c/imx/Makefile

@@ -7,5 +7,7 @@ obj-$(CONFIG_VIDEO_OV8858)     += ov8858_driver.o
 
 # HACK! While this driver is in bad shape, don't enable several warnings
 #       that would be otherwise enabled with W=1
-ccflags-y += -Wno-unused-but-set-variable -Wno-missing-prototypes \
-             -Wno-unused-const-variable -Wno-missing-declarations
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+ccflags-y += $(call cc-disable-warning, unused-const-variable)
+ccflags-y += $(call cc-disable-warning, missing-prototypes)
+ccflags-y += $(call cc-disable-warning, missing-declarations)

drivers/staging/media/atomisp/i2c/ov5693/Makefile

@@ -2,5 +2,7 @@ obj-$(CONFIG_VIDEO_OV5693) += ov5693.o
 
 # HACK! While this driver is in bad shape, don't enable several warnings
 #       that would be otherwise enabled with W=1
-ccflags-y += -Wno-unused-but-set-variable -Wno-missing-prototypes \
-             -Wno-unused-const-variable -Wno-missing-declarations
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+ccflags-y += $(call cc-disable-warning, unused-const-variable)
+ccflags-y += $(call cc-disable-warning, missing-prototypes)
+ccflags-y += $(call cc-disable-warning, missing-declarations)