r8169: move PHY regs tables to .rodata

As side effect, consume less stack.

	-rtl8169_get_mac_version [vmlinux]:	432
	-rtl8169_init_one [vmlinux]:		376
	+rtl8169_init_one [vmlinux]:		136

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>