MAINTAINERS: correct the path of UEFI docs

Change the path from doc/uefi to doc/develop/uefi.

Fixes: commit d1ceeeff ("doc: Move UEFI under develop/")
Signed-off-by: NAKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>

MAINTAINERS

@@ -695,7 +695,7 @@ R:	Alexander Graf <agraf@csgraf.de>
 S:	Maintained
 T:	git https://source.denx.de/u-boot/custodians/u-boot-efi.git
 F:	doc/api/efi.rst
-F:	doc/uefi/*
+F:	doc/develop/uefi/*
 F:	doc/usage/bootefi.rst
 F:	drivers/rtc/emul_rtc.c
 F:	include/capitalization.h