ipack: fix ipack.h kernel-doc warnings

ipack: fix ipack.h kernel-doc warnings

Fix various kernel-doc warnings in ipack.h:

 - Remove an empty kernel-doc comment.
 - Add 2 missing struct short descriptions.
 - Fix a typo in a description.
 - Add a missing struct field description.
 - Add some missing Return descriptions.
 - Clarify one function short description.

Warning: ../include/linux/ipack.h:73 Cannot find identifier on line:
 */
Warning: ../include/linux/ipack.h:74 Cannot find identifier on line:
struct ipack_region {
Warning: ../include/linux/ipack.h:75 Cannot find identifier on line:
        phys_addr_t start;
Warning: ../include/linux/ipack.h:76 Cannot find identifier on line:
        size_t      size;
Warning: ../include/linux/ipack.h:77 Cannot find identifier on line:
};
Warning: ../include/linux/ipack.h:78 Cannot find identifier on line:

Warning: ../include/linux/ipack.h:79 Cannot find identifier on line:
/**
Warning: ipack.h:80 missing initial short description on line:
 *      struct ipack_device
Warning: ipack.h:163 missing initial short description on line:
 *      struct ipack_bus_device
Warning: ipack.h:130 struct member 'id_table' not described in 'ipack_driver'
Warning: ipack.h:189 No description found for return value of 'ipack_bus_register'
Warning: ipack.h:194 No description found for return value of 'ipack_bus_unregister' ***
Warning: ipack.h:202 No description found for return value of 'ipack_driver_register'
Warning: ipack.h:221 No description found for return value of 'ipack_device_init'
Warning: ipack.h:236 No description found for return value of 'ipack_device_add'
Warning: ipack.h:271 No description found for return value of 'ipack_get_carrier'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Link: https://patch.msgid.link/20251016033543.1142049-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>