Blackfin arch: Add peripheral io API to gpio header file

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

include/asm-blackfin/mach-bf548/gpio.h

@@ -210,3 +210,7 @@ struct gpio_port_t {
 	unsigned int port_mux;
 };
 
+int gpio_request(unsigned short gpio, const char *label);
+void peripheral_free(unsigned short per);
+int peripheral_request_list(unsigned short per[], const char *label);
+void peripheral_free_list(unsigned short per[]);