As cpuid= can be used with two syntaxes (one as a list, the other as a
string), we need to distinguish them without an error message. Introduce 
a helper function to detect the type of entry used before issuing a warning.

Signed-off-by: Andre Przywara

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Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12