The SVQ1 decoder does not need mpegvideo or rl.c, but it uses stuff
from h263data.c. But since 61fe4815
h263data.c called ff_rl_init() and this of course led to build errors
when the SVQ1 decoder is enabled and mpegvideo disabled.

Fix this by moving ff_h263_init_rl_inter() to h263.c.
Fixes ticket #9224.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>