ASoC: msm8952: add new backends for RX and TX

Slimbus to i2s bridge uses Slimbus2 TX and Slimbus4 RX
as backends. Hence add required dailinks.

CRs-Fixed: 2039443
Change-Id: I13b83cbfe59e3893490809568f0bcf1b0d96663c
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>