memory: stm32_omm: fix child clock leak on set_amcr() error path

When the mux is enabled, stm32_omm_configure() enables the two OSPI
child clocks via stm32_omm_toggle_child_clock(dev, true); they are meant
to stay enabled for the device's lifetime and are disabled again in
stm32_omm_remove() and on the devm_of_platform_populate() error path.

However, if the subsequent stm32_omm_set_amcr() call fails, the function
jumps to the "error:" label which only calls pm_runtime_put_sync_suspend()
before returning, leaving the two child clocks enabled. As this happens
during probe, the error is propagated and .remove() is never called, so
the clock enable references are leaked. devm_clk_bulk_get() only releases
the clock handles on unwind, it does not undo clk_prepare_enable().

Disable the child clocks on the set_amcr() error path, mirroring the
cleanup already done on the devm_of_platform_populate() failure path.

Fixes: 8181d061dcff ("memory: Add STM32 Octo Memory Manager driver")
Cc: stable@vger.kernel.org
Signed-off-by: Diego Fernando Mancera Gomez <diegomancera.dev@gmail.com>
Link: https://patch.msgid.link/20260917235925.44185-1-diegomancera.dev@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>