PCI: microchip: 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/pcie-microchip-host.c:866:32: warning: cast from 'void (*)(struct clk *)' to 'void (*)(void *)' converts to incompatible function type [-Wcast-function-type-strict]
          devm_add_action_or_reset(dev, (void (*) (void *))clk_disable_unprepare,
                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
No functional changes are intended.

Fixes: 6f15a9c9 ("PCI: microchip: Add Microchip PolarFire PCIe controller driver")
Link: https://lore.kernel.org/linux-pci/20230629165956.237832-3-kwilczynski@kernel.org
Link: https://lore.kernel.org/linux-pci/20230511-pci-microchip-clk-cast-v1-1-7674f4d4e218@kernel.org
Link: https://lore.kernel.org/linux-pci/20230111125323.1911373-3-daire.mcnamara@microchip.com


Co-developed-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
Co-developed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Simon Horman <horms@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>