gpio: uapi: use 0xB4 as ioctl() major

The previous 'o' is in conflict and not very orderly assigned.
We want to select an ioctl() major that does not conflict with
the existining ones.

Add the new reserved major (0xB4) to Documentation/ioctl/ioctl-number.txt

Fixes: 3c702e99 ("gpio: add a userspace chardev ABI for GPIOs")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/ioctl/ioctl-number.txt

@@ -319,6 +319,7 @@ Code  Seq#(hex)	Include File		Comments
 					<mailto:vgo@ratio.de>
 0xB1	00-1F	PPPoX			<mailto:mostrows@styx.uwaterloo.ca>
 0xB3	00	linux/mmc/ioctl.h
+0xB4	00-0F	linux/gpio.h		<mailto:linux-gpio@vger.kernel.org>
 0xC0	00-0F	linux/usb/iowarrior.h
 0xCA	00-0F	uapi/misc/cxl.h
 0xCA	80-8F	uapi/scsi/cxlflash_ioctl.h

include/uapi/linux/gpio.h

@@ -52,7 +52,7 @@ struct gpioline_info {
 	char consumer[32];
 };
 
-#define GPIO_GET_CHIPINFO_IOCTL _IOR('o', 0x01, struct gpiochip_info)
-#define GPIO_GET_LINEINFO_IOCTL _IOWR('o', 0x02, struct gpioline_info)
+#define GPIO_GET_CHIPINFO_IOCTL _IOR(0xB4, 0x01, struct gpiochip_info)
+#define GPIO_GET_LINEINFO_IOCTL _IOWR(0xB4, 0x02, struct gpioline_info)
 
 #endif /* _UAPI_GPIO_H_ */