PCI/ERR: Rename pci_aer_clear_device_status() to pcie_clear_device_status()

PCI/ERR: Rename pci_aer_clear_device_status() to pcie_clear_device_status()

pci_aer_clear_device_status() clears the error bits in the PCIe Device
Status Register (PCI_EXP_DEVSTA).  Every PCIe device has this register,
regardless of whether it supports AER.

Rename pci_aer_clear_device_status() to pcie_clear_device_status() to make
clear that it is PCIe-specific but not AER-specific.  Move it to
drivers/pci/pci.c, again since it's not AER-specific.  No functional change
intended.

Link: https://lore.kernel.org/r/20200717195619.766662-1-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>