Bluetooth: Remove kernel-doc style comment block

This patch changes the kernel-doc style comment block to common comment
block. These files don't support kernel-doc style so no need to use the
kernel-doc style. Also, they cause the warning when W=1 option is used
as below.

drivers/bluetooth/hci_ll.c:518: warning: Function parameter or member 'lldev' not described in 'download_firmware'
drivers/bluetooth/btmrvl_debugfs.c:29: warning: cannot understand function prototype: 'struct btmrvl_debugfs_data '
drivers/bluetooth/btmrvl_sdio.c:36: warning: expecting prototype for Marvell BT-over-SDIO driver(). Prototype was for VERSION() instead

Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>