Microblaze little-endian toolchain exports __MICROBLAZEEL__
which is used in the kernel to identify little/big endian.

The most of the changes are in loading values from DTB which
is always big endian.

Little endian platforms are based on new AXI bus which has
impact to early uartlite initialization.
Signed-off-by: NMichal Simek <monstr@monstr.eu>

it assumes we have an unaligned exception handler which

 (a) may not be true
 (b) costs a lot of performance
 Instead we'll use struct/union method for big endian accesses,
  and byte-shifting for little endian.
Signed-off-by: NJohn Williams <john.williams@petalogix.com>

Reviewed-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NJohn Linn <john.linn@xilinx.com>
Acked-by: NStephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: NJohn Williams <john.williams@petalogix.com>
Signed-off-by: NMichal Simek <monstr@monstr.eu>