[MIPS] EMMA2RH: Disable GEN_RTC, it can't possibly work.

Neither rtc_mips_get_time nor rtc_mips_set_time are being initialized by
the EMMA2RH setup code, so genrtc at best was a RTC dummy avoiding a few
error messages but not providing actual functionality.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/configs/emma2rh_defconfig

@@ -951,8 +951,7 @@ CONFIG_LEGACY_PTY_COUNT=256
 # CONFIG_WATCHDOG is not set
 # CONFIG_HW_RANDOM is not set
 CONFIG_RTC=m
-CONFIG_GEN_RTC=m
-CONFIG_GEN_RTC_X=y
+# CONFIG_GEN_RTC is not set
 # CONFIG_DTLK is not set
 # CONFIG_R3964 is not set
 # CONFIG_APPLICOM is not set