utzig/ChibiOS-Kinetis — pull request #3 by cdbennett (2013-08-12 22:33:54+00:00)
Title: Fix UARTx_S1 flag clearing in serial_lld.c.

The flags in S1 are write-1-to-clear, so the |= operation was actually
clearing *all* set flags in the S1 register regardless.