macremapper: drop VERSION definition in Makefile

By default Kernel modules follow the version schema from openwrt.git,
which happens to be APK compatible. Instead of defining a entirely
custom format, use what's already out there.

This patch drops the individual VERSION definition.

Right now, the version becomes 6.1.82.1.1.0-r2

Signed-off-by: Paul Spooren <mail@aparcar.org>