btrfs: Drop get_supported_operations.

Nothing ever calls it. The actually important method is the
file_system_module_info's DDM flags.

src/add-ons/kernel/file_systems/btrfs/kernel_interface.cpp

@@ -1052,21 +1052,6 @@ btrfs_remove_attr(fs_volume* _volume, fs_vnode* vnode,
 	return EROFS;
 }
 
-static uint32
-btrfs_get_supported_operations(partition_data* partition, uint32 mask)
-{
-#if 0
-	// TODO: We should at least check the partition size.
-	return B_DISK_SYSTEM_SUPPORTS_INITIALIZING
-		| B_DISK_SYSTEM_SUPPORTS_CONTENT_NAME
-		| B_DISK_SYSTEM_SUPPORTS_WRITING
-		;
-#else
-	return 0;
-#endif
-}
-
-
 static status_t
 btrfs_initialize(int fd, partition_id partitionID, const char* name,
 	const char* parameterString, off_t partitionSize, disk_job_id job)
@@ -1253,9 +1238,11 @@ static file_system_module_info sBtrfsFileSystem = {
 
 	// DDM flags
 	0
+#if 0
 	| B_DISK_SYSTEM_SUPPORTS_INITIALIZING
 	| B_DISK_SYSTEM_SUPPORTS_CONTENT_NAME
 //	| B_DISK_SYSTEM_SUPPORTS_WRITING
+#endif
 	,
 
 	// scanning
@@ -1266,9 +1253,8 @@ static file_system_module_info sBtrfsFileSystem = {
 
 	&btrfs_mount,
 
-
 	/* capability querying operations */
-	&btrfs_get_supported_operations,
+	NULL,	// get_supported_operations
 
 	NULL,	// validate_resize
 	NULL,	// validate_move