ARM: multi_v7_defconfig: remove redundant entries and re-enable TI_EDMA

TI_EDMA fell out of automatically selected options in the multi_v7
defconfig due to a select being removed from the davinci Kconfig entry. So
we need to re-enable explicitly to not regress some platforms.

The rest is just the result of running 'make multi_v7_defconfig + make
savedefconfig' to remove entries that are no longer needed due to changed
dependencies/selects or defaults.

Signed-off-by: Olof Johansson <olof@lixom.net>