Fixes the following W=1 kernel build warning(s):

 drivers/thunderbolt/eeprom.c:19: warning: Function parameter or member 'sw' not described in 'tb_eeprom_ctl_write'
 drivers/thunderbolt/eeprom.c:19: warning: Function parameter or member 'ctl' not described in 'tb_eeprom_ctl_write'
 drivers/thunderbolt/eeprom.c:27: warning: Function parameter or member 'sw' not described in 'tb_eeprom_ctl_read'
 drivers/thunderbolt/eeprom.c:27: warning: Function parameter or member 'ctl' not described in 'tb_eeprom_ctl_read'
 drivers/thunderbolt/eeprom.c:27: warning: expecting prototype for tb_eeprom_ctl_write(). Prototype was for tb_eeprom_ctl_read() instead
 drivers/thunderbolt/eeprom.c:43: warning: Function parameter or member 'sw' not described in 'tb_eeprom_active'
 drivers/thunderbolt/eeprom.c:43: warning: Function parameter or member 'enable' not described in 'tb_eeprom_active'
 drivers/thunderbolt/eeprom.c:73: warning: Function parameter or member 'sw' not described in 'tb_eeprom_transfer'
 drivers/thunderbolt/eeprom.c:73: warning: Function parameter or member 'ctl' not described in 'tb_eeprom_transfer'
 drivers/thunderbolt/eeprom.c:73: warning: Function parameter or member 'direction' not described in 'tb_eeprom_transfer'
 drivers/thunderbolt/eeprom.c:97: warning: Function parameter or member 'sw' not described in 'tb_eeprom_out'
 drivers/thunderbolt/eeprom.c:97: warning: Function parameter or member 'val' not described in 'tb_eeprom_out'
 drivers/thunderbolt/eeprom.c:117: warning: Function parameter or member 'sw' not described in 'tb_eeprom_in'
 drivers/thunderbolt/eeprom.c:117: warning: Function parameter or member 'val' not described in 'tb_eeprom_in'
 drivers/thunderbolt/eeprom.c:138: warning: Function parameter or member 'sw' not described in 'tb_eeprom_get_drom_offset'
 drivers/thunderbolt/eeprom.c:138: warning: Function parameter or member 'offset' not described in 'tb_eeprom_get_drom_offset'
 drivers/thunderbolt/eeprom.c:170: warning: Function parameter or member 'sw' not described in 'tb_eeprom_read_n'
 drivers/thunderbolt/eeprom.c:170: warning: Function parameter or member 'offset' not described in 'tb_eeprom_read_n'
 drivers/thunderbolt/eeprom.c:170: warning: Function parameter or member 'val' not described in 'tb_eeprom_read_n'
 drivers/thunderbolt/eeprom.c:170: warning: Function parameter or member 'count' not described in 'tb_eeprom_read_n'
 drivers/thunderbolt/eeprom.c:383: warning: Function parameter or member 'sw' not described in 'tb_drom_parse_entries'
 drivers/thunderbolt/eeprom.c:417: warning: Function parameter or member 'sw' not described in 'tb_drom_copy_efi'
 drivers/thunderbolt/eeprom.c:417: warning: Function parameter or member 'size' not described in 'tb_drom_copy_efi'

Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[ mw: Demote only static functions ]
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>