wil6210: move pre-FW configuration to separate function

Re-arrange the code to have dedicated function for device configuration
which takes place before FW starts running.

Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>