Patch from Marc Singer

Add support for the LPD7a40x implementation of the SMC91x ethernet
controller. This patch exists to work around a mismatch between the
way the LH7a40x CPUs handle chip selects and what the ethernet
controller expects.

This patch has been revised to eliminate masking of interrupts.  The
concessions are that 

  a) the ISR must perform an IOBARRIER before the first access to the
     chip, just in case the interrupt occurred while the driver was
     writing to the chip
  b) other drivers that use the same chip select region as the SMC
     chip must perform a similar IOBARRIER at the top of their ISRs.

Signed-off-by: Marc Singer
Signed-off-by: Russell King