doc: Update documentation URL

Update to use the new docs.u-boot.org URL for documentation.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 92814a4..d77b9ff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -979,7 +979,7 @@
 M:	Simon Glass <sjg@chromium.org>
 M:	Heinrich Schuchardt <xypron.glpk@gmx.de>
 S:	Maintained
-W:	https://u-boot.readthedocs.io/en/latest/develop/uefi/u-boot_on_efi.html
+W:	https://docs.u-boot.org/en/latest/develop/uefi/u-boot_on_efi.html
 F:	board/efi/efi-x86_app
 F:	configs/efi-x86_app*
 F:	doc/develop/uefi/u-boot_on_efi.rst