imx: Add SeeedStudio NPI-IMX6ULL Support

CPU:   Freescale i.MX6ULL rev1.1 792 MHz (running at 396 MHz)
CPU:   Industrial temperature grade (-40C to 105C) at 49C
Reset cause: POR
Model: Seeed NPi iMX6ULL Dev Board with NAND
Board: Seeed NPi i.MX6ULL Dev Board
DRAM:  512 MiB
NAND:  512 MiB
MMC:   FSL_SDHC: 0
In:    serial@2020000
Out:   serial@2020000
Err:   serial@2020000
Net:   FEC0

Working:
- Eth0
- MMC/SD
- NAND
- UART 1
- USB host

Signed-off-by: Navin Sankar Velliangiri <navin@linumiz.com>

Note:

Changes in v2:

 * removed unnecessary space in imx6ull-seeed-npi-imx6ull-dev-board.dts file.
 * Used SZ_2M for CONFIG_SYS_MALLOC_LEN size allocation.
diff --git a/board/seeed/npi_imx6ull/MAINTAINERS b/board/seeed/npi_imx6ull/MAINTAINERS
new file mode 100644
index 0000000..c6a915c
--- /dev/null
+++ b/board/seeed/npi_imx6ull/MAINTAINERS
@@ -0,0 +1,9 @@
+NPI_IMX6ULL BOARD
+M:	Navin Sankar Velliangiri <navin@linumiz.com>
+S:	Maintained
+F:	arch/arm/dts/imx6ull-seeed-npi-imx6ull-dev-board.dts
+F:	arch/arm/dts/imx6ull-seeed-npi-imx6ull-u-boot.dtsi
+F:	arch/arm/dts/imx6ull-seeed-npi-imx6ull.dtsi
+F:	board/seeed/npi-imx6ull/
+F:	configs/seeed_npi_imx6ull_defconfig
+F:	include/configs/npi_imx6ull.h