PCI/AER: Update is_internal_error() to be non-static is_aer_internal_error()

PCI/AER: Update is_internal_error() to be non-static is_aer_internal_error()

The AER driver includes significant logic for handling CXL protocol errors.
The AER driver will be updated in the future to separate the AER and CXL
logic.

Rename the is_internal_error() function to is_aer_internal_error() as it
gives a more precise indication of the purpose. Make
is_aer_internal_error() non-static to allow for the 2 different CXL
topology error model implementations (RCH and VH) to share this helper.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Link: https://patch.msgid.link/20260114182055.46029-11-terry.bowman@amd.com
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>