qcom: llcc/edac: Support polling mode for ECC handling

Not all Qcom platforms support IRQ mode for ECC handling. For those
platforms, the current EDAC driver will not be probed due to missing ECC
IRQ in devicetree.

So add support for polling mode so that the EDAC driver can be used on all
Qcom platforms supporting LLCC.

The polling delay of 5000ms is chosen based on Qcom downstream/vendor
driver.

Reported-by: Luca Weiss <luca.weiss@fairphone.com>
Tested-by: Luca Weiss <luca.weiss@fairphone.com>
Tested-by: Steev Klimaszewski <steev@kali.org> # Thinkpad X13s
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sa8540p-ride
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230314080443.64635-14-manivannan.sadhasivam@linaro.org