rmihidtool: length check on find_token
rmihidtool: length check on find_token

Addresses security concern:

find_token does not check size of result buffer when writing, just
depends on caller to make sure input and output buffers are the same
length. This can lead to a stack buffer overflow if run with malicious
arguments (e.g. "-w AAAA...more.than.255...AAAA").

adlr/rmi4utils,adlr/rmi4utils