MAINTAINERS: add UEFI commands to EFI PAYLOAD

Add the following files to EFI PAYLOAD:

- cmd/bootefi.c
- cmd/efidebug.c
- cmd/eficonfig.c
- cmd/nvedit_efi.c

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

MAINTAINERS

@@ -889,6 +889,10 @@ M:	Ilias Apalodimas <ilias.apalodimas@linaro.org>
 S:	Maintained
 T:	git https://source.denx.de/u-boot/custodians/u-boot-efi.git
 F:	arch/arm/lib/*_efi.*
+F:	cmd/bootefi.c
+F:	cmd/eficonfig.c
+F:	cmd/efidebug.c
+F:	cmd/nvedit_efi.c
 F:	doc/api/efi.rst
 F:	doc/develop/uefi/*
 F:	doc/mkeficapsule.1