Commit d284e6ef ("treewide: convert mtd-mac-address-increment* to
generic implementation") renamed "mtd-mac-address-increment" property
to "mac-address-increment". Convert remaining usages that have been
added after that.

Fixes: f44e9334 ("ipq806x: provide WiFI mac-addresses from dts")
Signed-off-by: Sungbo Eo <mans0n@gorani.run>