configs: at91: sama7g54_curiosity: Add initial default configs

Add default configuration for nand-flash to boot the linux kernel.
Add default configuration for qspi-flash to boot the linux kernel.
Add default configuration for sd-card to boot the linux kernel.
Configs are synced with savedefconfig.

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