ASoC: remove saarb and tavorevb3 machine drivers

Support for PXA95x was removed in v3.8. This means that the Kconfig
symbols MACH_SAARB and MACH_TAVOREVB3 are no longer available. This
leaves the SoC Audio support for Marvell Saarb and Marvell Tavor EVB3
unbuildable. Remove these drivers too.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>