wcn36xx: Remove dead code in wcn36xx_smd_config_bss()

wcn36xx_smd_config_bss_v0() and wcn36xx_smd_config_bss_v1() have been
designed to operate in standalone fashion. As a result we can drop the
dead code now present in wcn36xx_smd_config_bss() and happily remove one
kzalloc from the BSS config path as we do so.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200910150631.2178970-8-bryan.odonoghue@linaro.org