Config: Exynos5800: Enable build for Peach-Pi

This adds following things :
- New config and defconfig for Peach-Pi board.
- Alterations in Kconfig and MAINTAINERS.
- Addition of CONFIG_EXYNOS5800.
- ADdition of exynos5800-peach-pi in dts list.

Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/board/samsung/smdk5420/MAINTAINERS b/board/samsung/smdk5420/MAINTAINERS
index e0f5c7a..1423f83 100644
--- a/board/samsung/smdk5420/MAINTAINERS
+++ b/board/samsung/smdk5420/MAINTAINERS
@@ -6,3 +6,5 @@
 F:	configs/peach-pit_defconfig
 F:	include/configs/smdk5420.h
 F:	configs/smdk5420_defconfig
+F:	include/configs/peach-pi.h
+F:	configs/peach-pi_defconfig