pmdamssql: make rpm build conditional on platform support
pmdamssql: make rpm build conditional on platform support

The SQLServer ODBC driver is only supported on x86_64, no point
building and installing the mssql PMDA on other platforms.

Resolves Red Hat BZ #1795804

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp