staging: sm750fb, fix typos

The code contained typos like "structur", "fointers", etc. Fix that.

No code change, only comments.

Signed-off-by: Matej Vasek <xvasek1@fi.muni.cz>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Teddy Wang <teddy.wang@siliconmotion.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <devel@driverdev.osuosl.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>