staging: fbtft: Add space around '='

This patch fixes the checkpatch.pl error:

ERROR: spaces required around that '=' (ctx:VxV)
+                       sdev->bits_per_word=9;
                                           ^

Signed-off-by: Helen Fornazier <helen.fornazier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>