hw/ide/core.c: Prevent SIGSEGV during migration

The other callers to blk_set_enable_write_cache() in this file
already check for s->blk == NULL.

Signed-off-by: Don Slutz <[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Message-id: [email protected]
Cc: [email protected]
Signed-off-by: Peter Maydell <[email protected]>
(cherry picked from commit 6b896ab)

Conflicts:
	hw/ide/core.c

*removed dependency on 4be7463

Signed-off-by: Michael Roth <[email protected]>

Author: Don Slutz

hw/ide/core.c

@@ -2299,7 +2299,7 @@ static int ide_drive_post_load(void *opaque, int version_id)
 {
     IDEState *s = opaque;
 
-    if (s->identify_set) {
+    if (s->bs && s->identify_set) {
         bdrv_set_enable_write_cache(s->bs, !!(s->identify_data[85] & (1 << 5)));
     }
     return 0;