avcodec/h264_levels, h265_profile_level: Avoid relocations

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>

libavcodec/h264_levels.h

@@ -23,7 +23,7 @@
 #include <stdint.h>
 
 typedef struct H264LevelDescriptor {
-    const char *name;
+    char        name[4];    // Large enough for all current levels like "4.1"
     uint8_t     level_idc;
     uint8_t     constraint_set3_flag;
     uint32_t    max_mbps;

libavcodec/h265_profile_level.h

@@ -25,7 +25,7 @@
 
 
 typedef struct H265LevelDescriptor {
-    const char *name;
+    char        name[4];    // Large enough for all current levels like "4.1"
     uint8_t     level_idc;
 
     // Table A.6.