powerpc/powernv: More little endian issues in OPAL RTC driver

Sparse caught an issue where opal_set_rtc_time was incorrectly
byteswapping. Also fix a number of sparse warnings.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2 files changed