FAT: Fix 32 bit gcc2 compile.

You can't initialize struct fields in the declaration in gcc2, but you
can set them up in a constructor.  So made one for struct diri,
and initialize nested sub-structures too.

Change-Id: Ic8b824bc157cca4cdb8c4e41afdca596776c0d55
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4995
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

src/add-ons/kernel/file_systems/fat/iter.cpp

@@ -306,6 +306,16 @@ diri_init(nspace *vol, uint32 cluster, uint32 index, struct diri *diri)
 }
 
 
+diri::diri()
+{
+	csi.vol = NULL;
+	csi.cluster = 0;
+	csi.sector = 0;
+
+	current_block = NULL;
+}
+
+
 diri::~diri()
 {
 	if (current_block != NULL)

src/add-ons/kernel/file_systems/fat/iter.h

@@ -34,11 +34,12 @@ status_t csi_write_block(struct csi *csi, uint8 *buffer);
 
 /* directory entry iterator */
 struct diri {
-	struct csi csi = {};
+	struct csi csi;
 	uint32 starting_cluster;
 	uint32 current_index;
-	uint8 *current_block = NULL;
+	uint8 *current_block;
 
+	diri();
 	~diri();
 };