ARM: clps711x: serial driver hungs are a result of call disable_irq within ISR

Since 2.6.30-rc1 clps711x serial driver hungs system. This is a result
of call disable_irq from ISR. synchronize_irq waits for end of interrupt
and goes to infinite loop. This patch fix this problem.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>