mtd: sst25l: remove unnecessary MTD_DEBUG_LEVEL2 messages

All the SST25L series flash parts have uniform erase sectors.  Remove
the extra MTD_DEBUG_LEVEL2 messages showing the eraseregions info
since they could never be shown.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>