icnss2: Correct bdf file name formation

ICNSS2 platform driver form bdf file name based on board id
and download bdf data to FW. Correct the formation of file
name based on board id.

Change-Id: I3a101d04f19199b10f9fa6d869f3f436eb88b4b2
Signed-off-by: Naman Padhiar <npadhiar@codeaurora.org>