wil6210: extract firmware version from file header

Currently the FW version is taken from the sw_version field
of the FW ready event. This version is based on internal
version control revision and it is difficult to map to actual
FW version.
Fix this by using the actual FW version stored in the FW file
header record.

Change-Id: I37ac0cf1845c96e6d9e0f8fffd6481e8c32efa50
Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Git-commit: 13cd9f758a555d1ab547b0dbed3f9d1e529230c3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


CRs-Fixed: 1063261
Signed-off-by: Maya Erez <merez@codeaurora.org>