PCI/pwrctrl: generic: Rename pci-pwrctrl-slot as generic

PCI/pwrctrl: generic: Rename pci-pwrctrl-slot as generic

The driver is pretty generic and would fit for either PCI Slots or
endpoints connected to PCI ports, so rename the driver and module as
pci-pwrctrl-generic.

Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260220-topic-sm8650-ayaneo-pocket-s2-base-v5-3-1ad79caa1efa@linaro.org