BACKPORT: ACPI / APEI: Remove spurious GHES_TO_CLEAR check

ghes_notify_nmi() checks ghes->flags for GHES_TO_CLEAR before going
on to __process_error(). This is pointless as ghes_read_estatus()
will always set this flag if it returns success, which was checked
earlier in the loop. Remove it.

This patch is needed because Quicksilver firmware-first error handling
uses the SDEI notification type for communication between trusted
firmware and the OS. This adds needed NMI and SDEI functionality so
that the SDEI path in the kernel through APEI acts as an NMI and is
properly wired up to the APEI interfaces.

Backported from: torvalds/linux@7d49f2c

Signed-off-by: James Morse <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Signed-off-by: Tyler Baicar <[email protected]>

drivers/acpi/apei/ghes.c

@@ -940,9 +940,6 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
 			__ghes_panic(ghes, buf_paddr);
 		}
 
-		if (!(ghes->flags & GHES_TO_CLEAR))
-			continue;
-
 		__process_error(ghes);
 		ghes_clear_estatus(ghes, buf_paddr);
 	}