drivers/char: make efirtc.c driver explicitly non-modular

The Kconfig for this driver is currently:

config EFI_RTC
bool "EFI Real Time Clock Services"

...meaning that it currently is not being built as a module by anyone.
Lets remove all modular references, so that when reading the driver
there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We leave some tags like MODULE_LICENSE for documentation purposes.

Cc: Arnd Bergmann <[e-mail]>
Signed-off-by: Paul Gortmaker <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/char/efirtc.c

···
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/rtc.h>
 #include <linux/proc_fs.h>
···
 	}
 	return 0;
 }
+device_initcall(efi_rtc_init);
 
-static void __exit
-efi_rtc_exit(void)
-{
-	/* not yet used */
-}
-
-module_init(efi_rtc_init);
-module_exit(efi_rtc_exit);
-
+/*
 MODULE_LICENSE("GPL");
+*/