gpio_shell: support for input pull down/up

Add pull up/down in gpio shell.

Signed-off-by: Tomasz Duda <tomaszduda23@gmail.com>
diff --git a/drivers/gpio/gpio_shell.c b/drivers/gpio/gpio_shell.c
index af70a2e..37457d6 100644
--- a/drivers/gpio/gpio_shell.c
+++ b/drivers/gpio/gpio_shell.c
@@ -46,6 +46,10 @@
 		index = (uint8_t)atoi(argv[args_indx.index]);
 		if (!strcmp(argv[args_indx.mode], "in")) {
 			type = GPIO_INPUT;
+		} else if (!strcmp(argv[args_indx.mode], "inu")) {
+			type = GPIO_INPUT | GPIO_PULL_UP;
+		} else if (!strcmp(argv[args_indx.mode], "ind")) {
+			type = GPIO_INPUT | GPIO_PULL_DOWN;
 		} else if (!strcmp(argv[args_indx.mode], "out")) {
 			type = GPIO_OUTPUT;
 		} else {