MAINTAINERS: add cper to APEI files

The CPER records are defined as part of UEFI specs, but its
primary way to report it is via APEI/GHES. As such, let's
place it under the same umbrella to make easier for patch
review.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Author: mchehab

MAINTAINERS

@@ -314,6 +314,7 @@ R:	Mauro Carvalho Chehab <mchehab@kernel.org>
 R:	Shuai Xue <xueshuai@linux.alibaba.com>
 L:	linux-acpi@vger.kernel.org
 F:	drivers/acpi/apei/
+F:	drivers/firmware/efi/cper*
 
 ACPI COMPONENT ARCHITECTURE (ACPICA)
 M:	"Rafael J. Wysocki" <rafael@kernel.org>
@@ -9511,6 +9512,7 @@ F:	arch/arm/boot/compressed/efi-header.S
 F:	arch/x86/platform/efi/
 F:	drivers/firmware/efi/
 F:	include/linux/efi*.h
+X:	drivers/firmware/efi/cper*
 
 EXTERNAL CONNECTOR SUBSYSTEM (EXTCON)
 M:	MyungJoo Ham <myungjoo.ham@samsung.com>