staging: r8188eu: Remove pointless NULL check in rtw_check_join_candidate()

Clang warns:

drivers/staging/r8188eu/core/rtw_mlme.c:1629:28: warning: address of
array 'pmlmepriv->assoc_ssid.Ssid' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        if (pmlmepriv->assoc_ssid.Ssid && pmlmepriv->assoc_ssid.SsidLength) {
            ~~~~~~~~~~~~~~~~~~~~~~^~~~ ~~
1 warning generated.

Ssid is an array not at the beginning of a struct so its address cannot
be NULL so remove the check.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20210805185807.3296077-4-nathan@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>