boards: arm: Add support for R-Car H3ULCB board

Add basic configuration for H3ULCB, just enough to see the
Zephyr boot banner on the ram console.

This configuration make use of the Cortex-R7 present on
r8a977951 SoC.

Signed-off-by: Julien Massot <julien.massot@iot.bzh>
diff --git a/CODEOWNERS b/CODEOWNERS
index 8904e36..f73ffc2 100644
--- a/CODEOWNERS
+++ b/CODEOWNERS
@@ -130,6 +130,7 @@
 /boards/arm/stm32*_disco/                 @erwango @ABOSTM @FRASTM
 /boards/arm/stm32f3_disco/                @ydamigos
 /boards/arm/stm32*_eval/                  @erwango @ABOSTM @FRASTM
+/boards/arm/rcar_h3ulcb/                  @julien-massot
 /boards/common/                           @mbolivar-nordic
 /boards/deprecated.cmake                  @tejlmand
 /boards/nios2/                            @nashif