"fhemuptime" improvement

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6168 2b470e98-0d58-463d-a4d8-8e2adae1ed80
FRM: fix a crucial bug in perl-firmata parser skipping single 0x30 bytes on fast machines

git-svn-id: svn://svn.code.sf.net/p/fhem/code/trunk@6169 2b470e98-0d58-463d-a4d8-8e2adae1ed80