wilc1000: fix possible memory leak in cfg_scan_result()

When the BSS reference holds a valid reference, it is not freed. The 'if'
condition is wrong. Instead of the 'if (bss)' check, the 'if (!bss)' check
is used.
The issue is solved by removing the unnecessary 'if' check because
cfg80211_put_bss() already performs the NULL validation.

Fixes: 6cd4fa5a ("staging: wilc1000: make use of cfg80211_inform_bss_frame()")
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-3-ajay.kathat@microchip.com