Depending on the company is supplying the primers, primers for housekeeper miRNA are supplied. In the case of EXIQON, the use U6 primers as endogeous control.
I have not used it, but people from my previous lab did.
it is optimal to test more than 1 or use geometric average of multiple endogenous control U6,U48, RNAU19... In a more precise way it is better to calculate the stability of the chosen ctrl or simply search the articles or manuals cuz these kindof datacould be found among manuals of companies or even articles