clocksource/drivers/timer-imx-gpt: Fix potential memory leak

[ Upstream commit 8051a993ce222a5158bccc6ac22ace9253dd71cb ]

Fix coverity Issue CID 250382:  Resource leak (RESOURCE_LEAK).
Add kfree when error return.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231009083922.1942971-1-ping.bai@nxp.com


Signed-off-by: Sasha Levin <sashal@kernel.org>