Staging: sm750fb: fix do not add new typedefs warning

This patch fixes the checkpatch.pl warning: "WARNING: do not add new
typedefs". Hiding a variables of type 'struct' is not always a good
idea,because when we passing them as parameters we tempt to forget that
in this proces we work with  stack memory and allocatting struct on
stack is something that we should manage carefuly.

It is also delete the '_t' from the name of the structs and treat a line
over 80 character issue in ddk750_mode.c, that appear after my modification.

Signed-off-by: Mihaela Muraru <mihaela.muraru21@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>