brcmfmac: Fix for unable to return to visible SSID

Unable to change back to visiable SSID because there is
no disable hidden ssid routine.

Signed-off-by: Soontak Lee <soontak.lee@cypress.com>
Signed-off-by: Chi-Hsien Lin <chi-hsien.lin@cypress.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200618160739.21457-2-chi-hsien.lin@cypress.com