sdp: rework handling of 128bit types

The old cose was causing warnings:

```
/__w/libogc/libogc/bt-embedded/bt-embedded/services/sdp.c: In function 'uint128_from_64':
/__w/libogc/libogc/bt-embedded/bt-embedded/services/sdp.c:53:12: warning: 'ret' is used uninitialized [-Wuninitialized]
   53 |     return ret;
      |            ^~~
/__w/libogc/libogc/bt-embedded/bt-embedded/services/sdp.c:46:19: note: 'ret' declared here
   46 |     BteSdpUint128 ret;
      |                   ^~~
```

Author: mardy

bt-embedded/services/sdp.c

@@ -44,21 +44,19 @@ static inline BteSdpInt128 int128_from_64(int64_t v) {
 #else
 static inline BteSdpUint128 uint128_from_64(uint64_t v) {
     BteSdpUint128 ret;
-    uint64_t *parts = (void*)&ret;
 #if __BYTE_ORDER == __LITTLE_ENDIAN
-    parts[0] = v; parts[1] = 0;
+    ret.parts[0] = v; ret.parts[1] = 0;
 #else
-    parts[1] = v; parts[0] = 0;
+    ret.parts[1] = v; ret.parts[0] = 0;
 #endif
     return ret;
 }
 static inline BteSdpInt128 int128_from_64(int64_t v) {
     BteSdpUint128 ret;
-    int64_t *parts = (void*)&ret;
 #if __BYTE_ORDER == __LITTLE_ENDIAN
-    parts[0] = v; parts[1] = v > 0 ? 0 : -1;
+    ret.parts[0] = (uint64_t)v; ret.parts[1] = (uint64_t)(v > 0 ? 0 : -1);
 #else
-    parts[1] = v; parts[0] = v > 0 ? 0 : -1;
+    ret.parts[1] = (uint64_t)v; ret.parts[0] = (uint64_t)(v > 0 ? 0 : -1);
 #endif
     return ret;
 }

bt-embedded/services/sdp.h

@@ -15,7 +15,7 @@ typedef __int128 BteSdpInt128;
 typedef unsigned __int128 BteSdpUint128;
 #else
 typedef struct {
-    uint8_t bytes[16];
+    uint64_t parts[2];
 } BteSdpUint128;
 typedef BteSdpUint128 BteSdpInt128;
 #endif