H.264 and H.265 levels' names are usually of the form "x" or "x.y"
with x and y being single digits; the one exception are the H.264 1b
levels. All of those levels' names fit into a char[4] and it is likely
that this future levels will do so, too.

Therefore this commit changes the H26(4|5)LevelDescriptor structures
to use such a char [4] instead of a pointer to a const char. This makes
the structures smaller (when sizeof(char*) == 8) and avoids relocations,
thereby moving the corresponding arrays from .data.rel.ro into .rodata.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>