net: phy: marvell: consolidate phy status reading

marvell_read_status_page_an() always reads the PHY status register, but
marvell_update_link() has already done this.  Rather than wastefully
reading the register twice in quick succession, read it once in
marvell_read_status_page() and use the result for both.

This makes marvell_update_link() rather pointless, so move it into
marvell_read_status_page().

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>