clocksource/drivers/imx-sysctr: Drop IRQF_IRQPOLL

Per the Documentation,
IRQF_IRQPOLL is used for polling (only the interrupt that is registered
first in a shared interrupt is considered for performance reasons)
But this timer is not sharing interrupt line with others, and
actually irqpoll not work with this timer with IRQF_IRQPOLL set, so
drop the flag.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20211214120737.1611955-2-peng.fan@oss.nxp.com


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>