PCI: keembay: Remove cast between incompatible function type

PCI: keembay: Remove cast between incompatible function type

Rather than casting void(*)(struct clk *) to void (*)(void *), that
forces conversion to an incompatible function type, replace the cast
with a small local stub function with a signature that matches what
the devm_add_action_or_reset() function expects.

The sub function takes a void *, then passes it directly to
clk_disable_unprepare(), which handles the more specific type.

Reported by clang when building with warnings enabled:

  drivers/pci/controller/dwc/pcie-keembay.c:172:12: warning: cast from 'void (*)(struct clk *)' to 'void (*)(void *)' converts to incompatible function type [-Wcast-function-type-strict]
                                         (void(*)(void *))clk_disable_unprepare,
                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
No functional changes are intended.

Fixes: 0c87f90b4c13 ("PCI: keembay: Add support for Intel Keem Bay")
Link: https://lore.kernel.org/linux-pci/20230629165956.237832-2-kwilczynski@kernel.org
Acked-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>