Split parseSequenceHeaderProfile() into AV1 & AV2

Split the parseSequenceHeaderProfile() function into
parseAV1SequenceHeaderProfile() and parseAV2SequenceHeaderProfile() so
that they can each have their own validity checks.

src/obu.c

diff --git a/src/obu.c b/src/obu.c
index b96ce61..f07ace6 100644
--- a/src/obu.c
+++ b/src/obu.c
@@ -152,9 +152,20 @@
 //
 // Originally dav1d's parse_seq_hdr() function (heavily modified and split)
 
-static avifBool parseSequenceHeaderProfile(avifBits * bits, uint32_t numBits, avifSequenceHeader * header)
+static avifBool parseAV1SequenceHeaderProfile(avifBits * bits, avifSequenceHeader * header)
 {
-    uint32_t seq_profile = avifBitsRead(bits, numBits);
+    uint32_t seq_profile = avifBitsRead(bits, 3);
+    if (seq_profile > 2) {
+        return AVIF_FALSE;
+    }
+    header->av1C.seqProfile = (uint8_t)seq_profile;
+    return !bits->error;
+}
+
+#if defined(AVIF_CODEC_AVM)
+static avifBool parseAV2SequenceHeaderProfile(avifBits * bits, avifSequenceHeader * header)
+{
+    uint32_t seq_profile = avifBitsRead(bits, PROFILE_BITS);
 #if defined(CONFIG_AV2_PROFILES) && CONFIG_AV2_PROFILES
     if (seq_profile > 5) {
 #else
@@ -165,6 +176,7 @@
     header->av1C.seqProfile = (uint8_t)seq_profile;
     return !bits->error;
 }
+#endif // defined(AVIF_CODEC_AVM)
 
 static avifBool parseSequenceHeaderLevelIdxAndTier(avifBits * bits, avifSequenceHeader * header)
 {
@@ -439,7 +451,7 @@
 
 static avifBool parseAV1SequenceHeader(avifBits * bits, avifSequenceHeader * header)
 {
-    AVIF_CHECK(parseSequenceHeaderProfile(bits, 3, header));
+    AVIF_CHECK(parseAV1SequenceHeaderProfile(bits, header));
     AVIF_CHECK(parseSequenceHeaderLevelIdxAndTier(bits, header));
 
     AVIF_CHECK(parseSequenceHeaderFrameMaxDimensions(bits, header));
@@ -466,7 +478,7 @@
         return AVIF_FALSE;
     }
 
-    AVIF_CHECK(parseSequenceHeaderProfile(bits, PROFILE_BITS, header));
+    AVIF_CHECK(parseAV2SequenceHeaderProfile(bits, header));
     header->reduced_still_picture_header = (uint8_t)avifBitsRead(bits, 1); // single_picture_header_flag
     if (!header->reduced_still_picture_header) {
         avifBitsRead(bits, 3); // seq_lcr_id