staging: vt6655: fix camelcase byData in card.c

staging: vt6655: fix camelcase byData in card.c

Replace camelcase variable "byData" into linux kernel coding style
equivalent variable "data" in card.c.
"by" prefix in hungarian notation stands for byte or unsigned char

References:
https://www.kernel.org/doc/html/latest/process/coding-style.html
https://www.cse.iitk.ac.in/users/dsrkg/cs245/html/Guide.htm

Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Link: https://lore.kernel.org/r/20211106184822.24242-1-tomm.merciai@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>