Revert "i2c: fix stack buffer overflow vulnerability in i2c md command"

This reverts commit 8f8c04bf.

The commit is largely wrong and breaks most of i2c command functionality.
The problem described in the aforementioned commit commit message is valid,
however the commit itself does many more changes unrelated to fixing that
one problem it describes. Those extra changes, namely the handling of i2c
device address length as unsigned instead of signed integer, breaks the
expectation that address length may be negative value. The negative value
is used by DM to indicate that address length of device does not change.

The actual bug documented in commit 8f8c04bf
can be fixed by extra sanitization in separate patch.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Nicolas Iooss <nicolas.iooss+uboot@ledger.fr>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Simon Glass <sjg@chromium.org>