Bluetooth: Add check for mgmt_alloc_skb() in mgmt_remote_name()

Add check for the return value of mgmt_alloc_skb() in
mgmt_remote_name() to prevent null pointer dereference.

Fixes: ba17bb62 ("Bluetooth: Fix skb allocation in mgmt_remote_name() & mgmt_device_connected()")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>