ASoC: lahaina: Update BTFM Tx codec dai name for slimbus_7 BE DAILINK

Update the codec dai name for slimbus_7 backend dailink used for BT use
cases.

Change-Id: I7330f95a106a7c5b3b9d8c588f93342d466d2d2c
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>