sh_eth: rename EESIPR bits

Since the  commit  b0ca2a21f769 ("sh_eth: Add support of SH7763 to sh_eth")
the *enum* declaring the EESIPR bits (interrupt mask) went out of sync with
the *enum* declaring the EESR bits (interrupt status) WRT  bit naming  and
formatting. I'd like to restore the consistency by using EESIPR as the bit
name prefix, renaming the *enum* to EESIPR_BIT, and (finally) renaming the
bits according to the available  Renesas SH77{34|63} manuals; additionally,
reconstruct  couple names using  the EESR bit declaration above...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>