mtd: physmap_of_gemini: remove defined but not used symbol 'syscon_match'

It's not used by anyone now, remove it. Fix the following gcc warning:

drivers/mtd/maps/physmap-gemini.c:49:34: warning: ‘syscon_match’ defined
but not used [-Wunused-const-variable=]
 static const struct of_device_id syscon_match[] = {
                                  ^~~~~~~~~~~~

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/maps/physmap-gemini.c

@@ -46,11 +46,6 @@
 
 #define FLASH_PARALLEL_HIGH_PIN_CNT	(1 << 20)	/* else low pin cnt */
 
-static const struct of_device_id syscon_match[] = {
-	{ .compatible = "cortina,gemini-syscon" },
-	{ },
-};
-
 struct gemini_flash {
 	struct device *dev;
 	struct pinctrl *p;