asoc: fix possible overflow issue for routing driver

The reg in soc_mixer_control is 32-bit. When using
SOC_SINGLE_EXT, the value of FE DAI ID which is passed
as shift(to be operated on the reg) may be more than 31,
which may cause overflow.
Use SOC_DOUBLE_EXT instead of SOC_SINGLE_EXT so that the reg
field can be set to SOC_NO_PM to avoid any DAPM operation,
while passing BE and FE IDs in shift and rshift fields. And
these values can be retrieve in get/put functions and use them.
This is to avoid any possible overflow in DAPM operation.

Change-Id: I17fa4e059889ae725e6f015a779f518e6d0a813f
Signed-off-by: Meng Wang <mwang@codeaurora.org>
Signed-off-by: Soumya Managoli <smanag@codeaurora.org>