drivers/rtc/rtc-pl031.c: do not mark PL031 IRQ as shared

It was a mistake to mark the PL031 IRQ as shared (for the U8500),
we misread the datasheet. Get rid of this.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Cc: Jonas Aberg <jonas.aberg@stericsson.com>
Cc: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>