sh_eth: make sh_eth_soft_swap() work on ARM

sh_eth: make sh_eth_soft_swap() work on ARM

Browsing  thru the driver disassembly, I noticed that ARM gcc generated
no  code  whatsoever for sh_eth_soft_swap() while building a little-endian
kernel -- apparently __LITTLE_ENDIAN__ was not being #define'd, however
it got implicitly #define'd when building with the SH gcc (I could only
find the explicit #define __LITTLE_ENDIAN that was #include'd when building
a little-endian kernel).  Luckily, the Ether controller  only doing big-
endian DMA is encountered on the early SH771x SoCs only and all ARM SoCs
implement EDMR.DE and thus set 'sh_eth_cpu_data::hw_swap'. But anyway, we
need to fix the #ifdef inside sh_eth_soft_swap() to something that would
work on all architectures...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: David S. Miller <davem@davemloft.net>