tg3: Correct NVRAM stream endian notations

Any software requesting NVRAM data as it exists on NVRAM is necessarily
requesting that the results be returned as a bytestream.  A bytestream
data read in from the device can also be thought to be in big endian
format.  Therefore, all the LE notations in the driver are mislabeled.
This patch converts all LE notations to BE notations, carefully
evaluating the surrounding code in the process.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>