net: pcs: xpcs: remove dw_xpcs_compat enum

net: pcs: xpcs: remove dw_xpcs_compat enum

There is no reason for the struct dw_xpcs_compat arrays to be a fixed
size other than the way we iterate over them. The index into the array
isn't used for anything, and having them fixed size needlessly wastes
space.

Remove the enum that defines their size, and instead use an empty
array entry (with NULL ->supported) to mark the end of the array.

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