Revert "ath11k: add read variant from SMBIOS for download board data"

This reverts commit 46e46db3

. Mark reported
that it breaks QCA6390 hw2.0 on Dell XPS 13 9310:

[    5.537034] ath11k_pci 0000:72:00.0: chip_id 0x0 chip_family 0xb board_id 0xff soc_id 0xffffffff
[    5.537038] ath11k_pci 0000:72:00.0: fw_version 0x101c06cc fw_build_timestamp 2020-06-24 19:50 fw_build_id
[    5.537236] ath11k_pci 0000:72:00.0: failed to fetch board data for bus=pci,qmi-chip-id=0,qmi-board-id=255,variant=DE_1901 from ath11k/QCA6390/hw2.0/board-2.bin
[    5.537255] ath11k_pci 0000:72:00.0: failed to fetch board-2.bin or board.bin from QCA6390/hw2.0
[    5.537257] ath11k_pci 0000:72:00.0: qmi failed to fetch board file: -2
[    5.537258] ath11k_pci 0000:72:00.0: failed to load board data file: -2

So we need to back to the drawing board and implement it so that backwards
compatiblity is not broken.

Reported-by: Mark Herbert <mark.herbert42@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211124094316.9096-1-kvalo@codeaurora.org