treewide: spelling: correct diffrent[iate] and banlance typos

Add these misspellings to scripts/spelling.txt too

Link: http://lkml.kernel.org/r/962aace119675e5fe87be2a88ddac1a5486f8e60.1490931810.git.joe@perches.com


Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>