[POWERPC] Fix FSL BookE machine check reporting

Reserved MCSR bits on FSL BookE parts may have spurious values
when mcheck occurs.  Mask these off when printing the MCSR to
avoid confusion.  Also, get rid of the MCSR_GL_CI bit defined
for e500 - this bit doesn't actually have any meaning.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>