mei: vsc: Use struct vsc_tp_packet as vsc-tp tx_buf and rx_buf type

mei: vsc: Use struct vsc_tp_packet as vsc-tp tx_buf and rx_buf type

vsc_tp.tx_buf and vsc_tp.rx_buf point to a struct vsc_tp_packet, use
the correct type instead of "void *" and use sizeof(*ptr) when allocating
memory for these buffers.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Link: https://lore.kernel.org/r/20250318141203.94342-3-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>