wil6210: support Talyn specific board file

FW file name for Talyn device can be different from the default name.
In such a case use a corresponding board file name.
If such a board file is not present FW download procedure will fail.

Change-Id: If5d4bc6af8a91d617039bc56bf58d47999bd9040
Signed-off-by: Maya Erez <merez@codeaurora.org>