net: hp100: fix always-true check for link up state

The operation ~(p100_inb(VG_LAN_CFG_1) & HP100_LINK_UP) returns a value
that is always non-zero and hence the wait for the link to drop always
terminates prematurely.  Fix this by using a logical not operator instead
of a bitwise complement.  This issue has been in the driver since
pre-2.6.12-rc2.

Detected by CoverityScan, CID#114157 ("Logical vs. bitwise operator")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>