toradex: tdx-cfg-block: rework display adapter name handling

Rework the rather big array of zero length strings with 4 entries of
actual display adapter names to a array of structs which ties a pid4
to its correspondent human readable string.
Provide an accessor to get the string for a given PID4.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>
diff --git a/board/toradex/common/tdx-cfg-block.h b/board/toradex/common/tdx-cfg-block.h
index 7486ffb..5dc9053 100644
--- a/board/toradex/common/tdx-cfg-block.h
+++ b/board/toradex/common/tdx-cfg-block.h
@@ -120,7 +120,7 @@
 int read_tdx_cfg_block(void);
 int read_tdx_cfg_block_carrier(void);
 const char * const get_toradex_carrier_boards(int pid4);
-
+const char * const get_toradex_display_adapters(int pid4);
 int try_migrate_tdx_cfg_block_carrier(void);
 
 void get_mac_from_serial(u32 tdx_serial, struct toradex_eth_addr *eth_addr);