ixgbe: Fix issues with EEPROM access

There are two problems with EEPROM access. One is that it needs to
hold the semaphore until the entire response is read or else the
response can be corrupted by other firmware accesses. The second
problem is that acquiring and releasing the semaphore is slow, so
it should be taken and released once when multiple EEPROM accesses
will be done.

Both of these issues can be solved by adding a new function,
ixgbe_hic_unlocked, to issue firmware commands that will assume
that the caller has acquired the needed semaphore.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>