ARM: imx_v6_v7_defconfig: update features

- Add sound support
- Enable mtd support
- Enable i.MX NAND support
- Enable NOR flash support
- Enable JFFS2/UBI
- Enable clk debugfs support
- Disable iommu support which is not present on i.MX
- Enable MC13xxx RTC
- Enable RNGA random number generator
- Enable SPI EEPROM support
- Enable I2C EEPROM support

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>