asoc: wcd9xxx-core: avoid slimbus read/write during ADSP SSR

This reverts commit 40bc50d768038c04f8c1 ("mfd: wcd9xxx-core:
Synchronize codec down and reset calls from slimbus.").
This is to make sure that the dev_up flag is set right
after device_down is called from Slimbus after ADSP SSR.
This flag helps make sure that all read/write calls over
slimbus are blocked until ADSP and Slimbus are fully up
post-SSR.

Change-Id: I5595a23a0b51f2ca392ddfb5773b057204185b54
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>