ENGR00290679 mxc: mlb Fix the MLB150 not stable issue in ISOC mode.

ENGR00290679 mxc: mlb Fix the MLB150 not stable issue in ISOC mode.

The MLB test bench has bug when testing the ISOC mode.When we press
stop test button when completing test, MITB will cause MLB150 on ARD
error.The mlbintr ISR handler is used to handle the error interrupt.
In the ISR handler, the MLB150_MS0,MLB150MS1 should be cleared.
The spec doesn't give detailed description. The spec only says that
the registers need to be cleared before enabling interrupt.

Signed-off-by: Luwei Zhou <b45643@freescale.com>