staging: sm7xxfb: use kernel commandline

We were only using the kernel commandline to set the mode if this driver
is builtin, but when it is built as a module we were not having any way
to set the mode. Start using commandline even if it is built as a
module.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>