powerpc: fix ALSA options in Freescale 85xx and 86xx defconfigs

The defconfigs for Freescale 85xx and 86xx SOCs had bad choices for some
audio related options.  In particular, OSS emulation should be enabled,
and the old ALSA API should be disabled.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>