Merge branch 'for-next/missing-prototypes'

lib: lodepng: remove useless test ...

Either the condition 'code_ll==(unsigned int)(-1)' is redundant or the
array 'LENGTHBASE[29]' is accessed at index 4294967038, which is out of
bounds.

On other hand this condition is tested within other scope:
"if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX)"
with is already limited to (code_ll >= 257 && code_ll <= 285),
so it can't be -1 any way.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: lodepng: Avoid missing prototypes warning ...

- move prototypes to header file
- remove some unused functions
- make locally used functions static.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: move gui file to include/gui and lib/gui ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>