edac: arm64: Add support for detecting Single Bit Errors

Single bit errors are detected using the PMU's memory event.
The counter overflow interrupt triggers a read of the
relevant CPU registers which help in reporting the single
bit errors.

Change-Id: I29cc3c952c1e0f1c05120b23cf30775583dcd67c
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>