PCI: dwc: Provide deinit callback for i.MX

PCI: dwc: Provide deinit callback for i.MX

The i.MX integration for the DesignWare PCI controller has a _host_exit()
operation which undoes everything that the _host_init() operation does but
does not wire this up as the host_deinit callback for the core, or call it
in any path other than suspend. This means that if we ever unwind the
initial probe of the device, for example because it fails, the regulator
core complains that the regulators for the device were left enabled:

imx6q-pcie 33800000.pcie: iATU: unroll T, 4 ob, 4 ib, align 64K, limit 16G
imx6q-pcie 33800000.pcie: Phy link never came up
imx6q-pcie 33800000.pcie: Phy link never came up
imx6q-pcie: probe of 33800000.pcie failed with error -110
------------[ cut here ]------------
WARNING: CPU: 2 PID: 46 at drivers/regulator/core.c:2396 _regulator_put+0x110/0x128

Wire up the callback so that the core can clean up after itself.

Link: https://lore.kernel.org/r/20230731-pci-imx-regulator-cleanup-v2-1-fc8fa5c9893d@kernel.org
Tested-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>