SA1100 and PXA RTC clean-ups This series enables building the SA1100 RTC driver for ARM64 in preparation for enabling CONFIG_ARCH_MMP on ARM64. This is needed for supporting the PXA1928 SOC. Clean-up of SA1100 RTC is complicated by the fact that some PXA chips use both sa1100-rtc and pxa-rtc drivers and share the same registers. This does not work well with the Linux driver model. So the first step is removing this sharing by the 2 drivers and making sa1100-rtc and pxa-rtc mutually exclusive.