common: board_r: include asm-generic/gpio.h

Not all architectures define <asm/gpio.h> and even on those that do, the
header cannot be included for all boards without causing various build
failures.

Since common/board_r.c only needs gpio_hog_probe_all() declaration, include
<asm-generic/gpio.h> and drop the associated ifdef.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
diff --git a/common/board_r.c b/common/board_r.c
index b891c84..f607ce7 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -66,9 +66,7 @@
 #include <linux/err.h>
 #include <efi_loader.h>
 #include <wdt.h>
-#if defined(CONFIG_GPIO_HOG)
-#include <asm/gpio.h>
-#endif
+#include <asm-generic/gpio.h>
 #ifdef CONFIG_EFI_SETUP_EARLY
 #include <efi_loader.h>
 #endif