T1040 has a different version of corenet-cf, despite being incorrectly
labelled with a fsl,corenet2-cf compatible.  The t1040 version of
corenet-cf has a version register that can be read to distinguish.  The
t4240/b4860 version officially does not, but testing shows that it does
and has a different value, so use that.  If somehow this ends up not
being reliable and we treat a t4240/b4860 as a t1040 (the reverse
should not happen, as t1040's version register is official), currently
the worst that should happen is writing to reserved bits to enable
events that don't exist.

The changes to the t1040 version of corenet-cf that this driver cares
about are the addition of two new error events.  There are also changes
to the format of cecar2, which is printed, but not interpreted, by this
driver.
Signed-off-by: Scott Wood <scottwood@freescale.com>