ethernet: codespell comment spelling fixes

To test a checkpatch spelling patch, I ran codespell against
drivers/net/ethernet/.

$ git ls-files drivers/net/ethernet/ | \
  while read file ; do \
    codespell -w $file; \
  done

I removed a false positive in e1000_hw.h

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index d6be4c69..52d01b8 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -30,7 +30,7 @@
  *
  * Neither the 82576 nor the 82580 offer registers wide enough to hold
  * nanoseconds time values for very long. For the 82580, SYSTIM always
- * counts nanoseconds, but the upper 24 bits are not availible. The
+ * counts nanoseconds, but the upper 24 bits are not available. The
  * frequency is adjusted by changing the 32 bit fractional nanoseconds
  * register, TIMINCA.
  *