Bluetooth: AMP: Use set_bit / test_bit for amp_mgr state

Using bit operations solves problems with multiple requests
and clearing state.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c
index 6b829b2..d459ed4 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -236,7 +236,7 @@
 
 	cp.max_len = cpu_to_le16(hdev->amp_assoc_size);
 
-	mgr->state = READ_LOC_AMP_ASSOC;
+	set_bit(READ_LOC_AMP_ASSOC, &mgr->state);
 	hci_send_cmd(hdev, HCI_OP_READ_LOCAL_AMP_ASSOC, sizeof(cp), &cp);
 }
 
@@ -250,7 +250,7 @@
 	cp.len_so_far = cpu_to_le16(0);
 	cp.max_len = cpu_to_le16(hdev->amp_assoc_size);
 
-	mgr->state = READ_LOC_AMP_ASSOC_FINAL;
+	set_bit(READ_LOC_AMP_ASSOC_FINAL, &mgr->state);
 
 	/* Read Local AMP Assoc final link information data */
 	hci_send_cmd(hdev, HCI_OP_READ_LOCAL_AMP_ASSOC, sizeof(cp), &cp);