base: Correct checkBpLen naming with checkBpKind

In gdb document*1, the second parameter of checkpoint command(Z0, Z1) is
named after kind. Although underlying implementation probably considers
it as length*2, it's still good to follow the name described in gdb
document for avoiding any confusion.

Refs:
1. https://sourceware.org/gdb/onlinedocs/gdb/Packets.html
2. https://github.com/bminor/binutils-gdb/blob/master/gdb/arch-utils.h#L41

Change-Id: Ib4b585613b8018970b16355f96cdff2ce9d5bae6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/54123
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
6 files changed