clk: pxa25x: OSTIMER0 clocks from the main oscillator

The OSTIMER0 clock ticks at the main oscillator rate, not the 32kHz
oscillator rate.  Ensure that it is parented to the main oscillator.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>