powerpc: gamecube_defconfig: Enable the RTC driver

This selects the rtc-gamecube driver, which provides a real-time clock
on this platform.
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211215175501.6761-5-linkmauve@linkmauve.fr

arch/powerpc/configs/gamecube_defconfig

@@ -68,7 +68,7 @@ CONFIG_SND_SEQUENCER=y
 CONFIG_SND_SEQUENCER_OSS=y
 # CONFIG_USB_SUPPORT is not set
 CONFIG_RTC_CLASS=y
-CONFIG_RTC_DRV_GENERIC=y
+CONFIG_RTC_DRV_GAMECUBE=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT4_FS=y
 CONFIG_ISO9660_FS=y