drivers: edac: Add polling and other support to edac driver

This change is a squash of the following commits taken from
msm-4.14.

1. commit <fdbf8562> ("drivers: edac: Use polling based
ECC if there is no ECC IRQ")
The current implementation of the LLCC's ECC mechanism
relies on an IRQ number, if the ECC IRQ number is not available,
default to polling based ECC to ensure that LLCC ECC errors do
not go by unnoticed.

2. commit <567f3826> ("drivers: edac: Allow IRQ line to
be shared")
Other drivers in the kernel might want to use the same interrupt
line that is used for llcc edac. Allow the interrupt line to be
shared with other drivers by marking the line as shared one.

Also, add required configs to control panic on correctable and
uncorrectable errors.

Change-Id: I4ef6a7aead8741e9a36eebf76c9cb44be3133981
Signed-off-by: Venkata Narendra Kumar Gutta <vnkgutta@codeaurora.org>