ARM: multi_v7_defconfig: Enable Zynq peripheral drivers

A few drivers for Zynq peripherals made it into mainline recently.
Enable them in the defconfig. The following devices are enabled:
 - Cadence Macb Ethernet controller
 - Cadence I2C controller
 - Arasan SDHCI

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Olof Johansson <olof@lixom.net>