staging: sm750fb: Remove typedef from "typedef struct _mode_parameter_t"

This patch removes typedefs from struct and renames it from "typedef
struct _mode_parameter_t" to "struct mode_parameter" as per kernel
coding standards."

Signed-off-by: Arushi Singhal <arushisinghal19971997@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>