Blackfin arch: add missing gpio.h header to fix compiling in some pm configurations

Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NBryan Wu <bryan.wu@analog.com>

arch/blackfin/mach-common/pm.c

@@ -39,7 +39,7 @@
 #include <asm/io.h>
 #include <asm/dpmc.h>
 #include <asm/irq.h>
-
+#include <asm/gpio.h>
 
 #ifdef CONFIG_PM_WAKEUP_GPIO_POLAR_H
 #define WAKEUP_TYPE	PM_WAKE_HIGH