Staging: bcm: Bcmchar.c: Renamed variable "PktLen" -> "pkt_len"

Renamed variable "PktLen" -> "pkt_len" in bcm_char_read().

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>