bus: fsl-mc: Fix potential double device reference in fsl_mc_get_endpoint()

bus: fsl-mc: Fix potential double device reference in fsl_mc_get_endpoint()

The fsl_mc_get_endpoint() function may call fsl_mc_device_lookup()
twice, which would increment the device's reference count twice if
both lookups find a device. This could lead to a reference count leak.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 1ac210d128ef ("bus: fsl-mc: add the fsl_mc_get_endpoint function")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 8567494cebe5 ("bus: fsl-mc: rescan devices if endpoint not found")
Link: https://patch.msgid.link/20250717022309.3339976-1-make24@iscas.ac.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>