net: pch_gbe: Remove read_mac_addr HAL abstraction

For some reason the pch_gbe driver contains a struct pch_gbe_functions
with pointers used by a HAL abstraction layer, even though there is only
one implementation of each function.

This patch removes the read_mac_addr abstraction in favor of calling
pch_gbe_mac_read_mac_addr directly. Since this is defined in the same
translation unit as all of its callers, we can make it static & remove
it from the pch_gbe.h header.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: David S. Miller <davem@davemloft.net>