Bluetooth: Prefer sizeof(*ptr) when allocating memory

It's safer practice to use sizeof(*ptr) instead of sizeof(ptr_type) when
allocating memory in case the type changes. This also fixes the
following style of warnings from static analyzers:

CHECK: Prefer kzalloc(sizeof(*ie)...) over kzalloc(sizeof(struct inquiry_entry)...)
+	ie = kzalloc(sizeof(struct inquiry_entry), GFP_KERNEL);

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>