drivers/net/sis190.c section fix

This patch fixes the following section mismatch with CONFIG_HOTPLUG=n:

<--  snip  -->

...
WARNING: vmlinux.o(.init.text.20+0x4cb25): Section mismatch: reference to .exit.text:sis190_mii_remove (between 'sis190_init_one' and 'read_eeprom')
...

<--  snip  -->

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>