x11/keymap,test/interactive-evdev: fix a couple of clang-analyzer warnings

From my analysis these values cannot be null, but the analyzer cannot
see this. So assert it.

Signed-off-by: Ran Benita <ran234@gmail.com>

src/x11/keymap.c

@@ -448,6 +448,7 @@ get_sym_maps(struct xkb_keymap *keymap, xcb_connection_t *conn,
                 const xkb_layout_index_t group = j / wire_sym_map->width;
                 const xkb_level_index_t level = j % wire_sym_map->width;
 
+                assert(key->groups[group].type != NULL);
                 if (level < key->groups[group].type->num_levels &&
                     wire_keysym != XKB_KEY_NoSymbol) {
                     key->groups[group].levels[level].num_syms = 1;

test/interactive-evdev.c

@@ -203,6 +203,7 @@ get_keyboards(struct xkb_keymap *keymap,
             continue;
         }
 
+        assert(kbd != NULL);
         kbd->next = kbds;
         kbds = kbd;
     }