baytrail: add audio clock workaround for LPE

Apparently the LPE device needs a 25MHz clock. Provide
the work around to enable this clock.

BUG=chrome-os-partner:23791
BRANCH=None
TEST=Built and booted. Confirmed setting being applied.

Change-Id: Ibff5563436b3025eb8b61ffee3302bd2da872b39
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175493
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/4928
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/soc/intel/baytrail/Makefile.inc

@@ -35,6 +35,7 @@ ramstage-y += southcluster.c
 ramstage-$(CONFIG_HAVE_REFCODE_BLOB) += refcode.c
 ramstage-y += sata.c
 ramstage-y += acpi.c
+ramstage-y += lpe.c
 
 # Remove as ramstage gets fleshed out
 ramstage-y += placeholders.c