common: cli_simple: use strlcpy instead of strcpy

Report Coverity log:
Destination buffer too small (STRING_OVERFLOW)
string_overflow: You might overrun the 1024 byte destination string
lastcommand by writing 1025 bytes from console_buffer

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>