staging: wilc1000: Remove unnecessary pointer check

Clang warns that the address of a pointer will always evaluated as true
in a boolean context:

drivers/staging/wilc1000/linux_wlan.c:267:20: warning: address of
'vif->ndev->dev' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        if (!(&vif->ndev->dev))
            ~  ~~~~~~~~~~~^~~
1 warning generated.

Since this statement always evaluates to false due to the logical not,
remove it.

Link: https://github.com/ClangBuiltLinux/linux/issues/121


Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>