ARM: rmobile: Unify Gen3 Salvator-X(S) and ULCB defconfigs

The r8a779{5,6,65}_salvator-x and r8a779{5,6,65}_ulcb_defconfig were
building the same target, except for the default DT. The default DT is
however only a detail, as the actual DT to be used to configure U-Boot
is detected automatically based on the CPU ID, hence the default DT is
not meaningful. Unify each three defconfigs per board to reduce the
duplication.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/board/renesas/ulcb/MAINTAINERS b/board/renesas/ulcb/MAINTAINERS
index 8549f54..564eb56 100644
--- a/board/renesas/ulcb/MAINTAINERS
+++ b/board/renesas/ulcb/MAINTAINERS
@@ -3,6 +3,4 @@
 S:	Maintained
 F:	board/renesas/ulcb/
 F:	include/configs/ulcb.h
-F:	configs/r8a7795_ulcb_defconfig
-F:	configs/r8a7796_ulcb_defconfig
-F:	configs/r8a77965_ulcb_defconfig
+F:	configs/rcar3_ulcb_defconfig