staging: vt6655: fix camelcase in bShortSlotTime

staging: vt6655: fix camelcase in bShortSlotTime

Replace camel case variable bShortSlotTime with snake case variable
short_slot_time. bShortSlotTime is a boolean variable, if true short
slot time is enabled, false not. Short Slot Time reduces the slot time
from 20 microseconds to 9 microseconds, where the slot time is
the maximum theoretical time for a frame to travel a network.

References:
 - http://cciew.blogspot.com/2011/02/short-slot-time.html
 - https://www.cse.wustl.edu/~jain/cse574-16/ftp/j_05lan4.pdf
 - https://www.networkdatapedia.com/post/2013/09/16/ \
   configuring-short-slot-time-to-improve-wifi-performance
 - https://en.wikipedia.org/wiki/Slot_time

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Link: https://lore.kernel.org/r/20211005205702.14029-2-tomm.merciai@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>