board: at91: sama5d29_curiosity: add initial support for sama5d29_curiosity

Add initial support for sama5d29_curiosity board.

Hardware:
SoC: SAMA5D29 500 MHz
DRAM: LPDDR2 512 MiB
PMIC: MCP16502
Debug: UART0
Flash: QSPI NOR 8 MiB
RGB LCD connector
Mikrobus connectors x 2
SD-Card connectors x 2
USB 2.0 x 2

Signed-off-by: Mihai Sain <mihai.sain@microchip.com>