wl12xx: Set correct REF CLK and TCXO CLK values to the FW

Fix mismatch between the REF CLK and TCXO CLK information that is
set in the platform data and the NVS, so we override what comes
from the NVS and replace it with what comes from the platform data.

[Small fix in a comment -- Luca]

Signed-off-by: Shahar Levi <shahar_levi@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>