staging: rtl8712: Remove NULL comparison

Remove NULL comparison by using '!' operator. Problem found
using checkpatch.pl
CHECK: Comparison to NULL could be written "!ptmpchar"

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed