MIPS: BCM47xx: fix build with GENERIC_GPIO configuration

Since eb9ae7f2 (gpio: fix build error in include/asm-generic/gpio.h)
the generic version of gpio.h calls __gpio_{set,get}_value which we
do not define. Get rid of asm-generic/gpio.h and define the missing
stubs directly for BCM47xx to build.
Reported-by: Ralf Baechle <ralf@linux-mips.org>
To: linux-mips@linux-mips.org
CC: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/2885/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-bcm47xx/gpio.h

@@ -36,6 +36,8 @@ static inline int gpio_get_value(unsigned gpio)
 	return -EINVAL;
 }
 
+#define gpio_get_value_cansleep	gpio_get_value
+
 static inline void gpio_set_value(unsigned gpio, int value)
 {
 	switch (bcm47xx_bus_type) {
@@ -54,6 +56,19 @@ static inline void gpio_set_value(unsigned gpio, int value)
 	}
 }
 
+#define gpio_set_value_cansleep gpio_set_value
+
+static inline int gpio_cansleep(unsigned gpio)
+{
+	return 0;
+}
+
+static inline int gpio_is_valid(unsigned gpio)
+{
+	return gpio < (BCM47XX_EXTIF_GPIO_LINES + BCM47XX_CHIPCO_GPIO_LINES);
+}
+
+
 static inline int gpio_direction_input(unsigned gpio)
 {
 	switch (bcm47xx_bus_type) {
@@ -137,7 +152,4 @@ static inline int gpio_polarity(unsigned gpio, int value)
 }
 
 
-/* cansleep wrappers */
-#include <asm-generic/gpio.h>
-
 #endif /* __BCM47XX_GPIO_H */