clocksource/drivers/gpx: Remove redundant casts

In the function gxp_timer_init, the 'int' type cast in front of the
PTR_ERR() macro is redundant, thus remove it.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20241107074619.2714-1-tangbin@cmss.chinamobile.com


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