USIM: export SELECT_ADF_USIM() as a function for the user

The user might want to select ADF.USIM at any later point
during a longer dialogue with the card (e.g. when the user
was in a diferent DF or the MF).  Hence, it's a good idea
to export this function.

Author: laf0rge

card/USIM.py

@@ -158,6 +158,9 @@ def __init__(self):
             log(3, '(UICC.__init__) type definition: %s' % type(self))
             log(3, '(UICC.__init__) CLA definition: %s' % hex(self.CLA))
 
+        self.SELECT_ADF_USIM()
+
+    def SELECT_ADF_USIM(self):
         # USIM selection from AID
         if self.dbg:
             log(3, '(USIM.__init__) UICC AID found:')