Revert "ath10k: Search SMBIOS for OEM board file extension"

This reverts commit f2593cb1

.

Paul reported that this patch with older board-2.bin ath10k initialisation
fails on Dell XPS 13:

ath10k_pci 0000:3a:00.0: failed to fetch board data for bus=pci,vendor=168c,
device=003e,subsystem-vendor=1a56,subsystem-device=1535,variant=RV_0520 from
ath10k/QCA6174/hw3.0/board-2.bin

The reason is that the older board-2.bin does not have the variant version of
the image name and ath10k does not fallback to the older naming scheme.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=185621#c9
Fixes: f2593cb1

 ("ath10k: Search SMBIOS for OEM board file extension")
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>