char/genrtc: remove alpha support

The genrtc driver serves no purpose on Alpha because it drives the
same hardware as the original rtc.c driver, and the newer rtc-generic.c
or rtc-cmos.c drivers on architectures that use the asm-generic/rtc.h
header.

The defconfig uses CONFIG_RTC=y, so this driver is not used by default.
At one point it was used to abstract a quirk for the "Marvel" platform,
but it does not do this any more after the code was moved into yet
another driver in arch/alpha/kernel/rtc.c.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/char/Kconfig

@@ -328,7 +328,7 @@ config JS_RTC
 config GEN_RTC
 	tristate "Generic /dev/rtc emulation"
 	depends on RTC!=y
-	depends on ALPHA || M68K || MN10300 || PARISC || PPC
+	depends on M68K || MN10300 || PARISC || PPC
 	---help---
 	  If you say Y here and create a character special file /dev/rtc with
 	  major number 10 and minor number 135 using mknod ("man mknod"), you