rtc: make definitions in include/uapi/linux/rtc.h actually useful for user space

BIT() macro is not defined in UAPI headers; there is, however, similarly
defined _BITUL() macro present in include/uapi/linux/const.h; use it
instead and include <linux/const.h> and <linux/ioctl.h> in order to make
the definitions provided in the header useful.

Fixes: 3431ca48 ("rtc: define RTC_VL_READ values")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Link: https://lore.kernel.org/r/20200324041209.GA30727@asgard.redhat.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

include/uapi/linux/rtc.h

@@ -12,6 +12,9 @@
 #ifndef _UAPI_LINUX_RTC_H_
 #define _UAPI_LINUX_RTC_H_
 
+#include <linux/const.h>
+#include <linux/ioctl.h>
+
 /*
  * The struct used to pass data via the following ioctl. Similar to the
  * struct tm in <time.h>, but it needs to be here so that the kernel
@@ -92,10 +95,10 @@ struct rtc_pll_info {
 #define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
 #define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
 
-#define RTC_VL_DATA_INVALID	BIT(0) /* Voltage too low, RTC data is invalid */
-#define RTC_VL_BACKUP_LOW	BIT(1) /* Backup voltage is low */
-#define RTC_VL_BACKUP_EMPTY	BIT(2) /* Backup empty or not present */
-#define RTC_VL_ACCURACY_LOW	BIT(3) /* Voltage is low, RTC accuracy is reduced */
+#define RTC_VL_DATA_INVALID	_BITUL(0) /* Voltage too low, RTC data is invalid */
+#define RTC_VL_BACKUP_LOW	_BITUL(1) /* Backup voltage is low */
+#define RTC_VL_BACKUP_EMPTY	_BITUL(2) /* Backup empty or not present */
+#define RTC_VL_ACCURACY_LOW	_BITUL(3) /* Voltage is low, RTC accuracy is reduced */
 
 #define RTC_VL_READ	_IOR('p', 0x13, unsigned int)	/* Voltage low detection */
 #define RTC_VL_CLR	_IO('p', 0x14)		/* Clear voltage low information */