.mailmap: Record all address for main U-Boot contributor

Based on looking at top contributors it was seen that top statistics from
top contributors don't include all contributions from different email
addresses. That's why I checked all top contributors are checked it.

git shortlog -n $START..$END -e -s

The patch is adding mapping for Bin Meng, Marek Vasut, Masahiro Yamada,
Michal Simek, Tom Rini, Wolfgang Denk.
And also use mapping for Stefan Roese and Wolfgang Denk to be properly
counted.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>