Update the tmicore platform's clock initialization. If DCO constants are in

INFOA, it uses them.  If not, is uses the standard mecthod of calibrating the
DCO off of ACLK.  For tmicore, DCOCLK = MCLK = 8MHz.  We add additional code to
set SMCLK = 1MHz.  If the constants are used, the 1MHz = 10^6HZ.  If the
internal cal routines are used, 1MHz = 2^20Hz.