gpio: add gpio-hog support

add gpio-hog support. GPIO hogging is a mechanism
providing automatic GPIO request and configuration
as part of the gpio-controller's driver probe function.

for more infos see:
doc/device-tree-bindings/gpio/gpio.txt

Signed-off-by: Heiko Schocher <hs@denx.de>
Tested-by: Michal Simek <michal.simek@xilinx.com> (zcu102)
Tested-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/common/board_r.c b/common/board_r.c
index df24021..abc31b1 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -49,6 +49,9 @@
 #include <linux/err.h>
 #include <efi_loader.h>
 #include <wdt.h>
+#if defined(CONFIG_DM_GPIO_HOG)
+#include <asm/gpio.h>
+#endif
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -796,6 +799,9 @@
 #ifdef CONFIG_CMD_NET
 	initr_ethaddr,
 #endif
+#if defined(CONFIG_DM_GPIO_HOG)
+	gpio_hog_probe_all,
+#endif
 #ifdef CONFIG_BOARD_LATE_INIT
 	board_late_init,
 #endif