soc: qcom: cmd-db: Use devm_memremap() to fix memory leak in cmd_db_dev_probe

soc: qcom: cmd-db: Use devm_memremap() to fix memory leak in cmd_db_dev_probe

If cmd_db_magic_matches() fails after memremap() succeeds, the function
returns -EINVAL without unmapping the memory region, causing a
potential resource leak.

Switch to devm_memremap to automatically manage the map resource.

Fixes: 312416d9171a ("drivers: qcom: add command DB driver")
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20251216013933.773-1-vulab@iscas.ac.cn
Signed-off-by: Bjorn Andersson <andersson@kernel.org>