ARM: 6454/1: sa1100: Fix for a nasty initialization bug in the RTSR.

ARM: 6454/1: sa1100: Fix for a nasty initialization bug in the RTSR.

This patch fixes a nasty initialization condition on the RTSR register.
Sometimes, bit 1 will wake up set, sometimes not. This can be seen
by checking the value of the RTSR by typing '$ cat /proc/driver/rtc',
which has been provided by the previous patch.

If this bit is set, the command '$ cat /dev/rtc0' will lock the system
in an endless interrupt routine calling loop.

This patch fixes the issue both at sa1100_rtc_probe(), where it avoids
a spurious interrupt from happening, and at sa1100_rtc_interrupt(),
which is the robust solution, though it does not avoid the first
spurious interrupt.

Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>