dm: zynq: Remove inline gpio functions

These functions serve no useful purpose, and conflict with the generic API.
Drop them.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-zynq/gpio.h

@@ -7,19 +7,4 @@
 #ifndef _ZYNQ_GPIO_H
 #define _ZYNQ_GPIO_H
 
-inline int gpio_get_value(unsigned gpio)
-{
-	return 0;
-}
-
-inline int gpio_set_value(unsigned gpio, int val)
-{
-	return 0;
-}
-
-inline int gpio_request(unsigned gpio, const char *label)
-{
-	return 0;
-}
-
 #endif /* _ZYNQ_GPIO_H */