rtc-parisc: remove redundant locking

The RTC subsystem proides ops locking, no need to implement our own

Signed-off-by: dann frazier <dannf@hp.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>