tg3: Fix 'scheduling while atomic' errors

This patch fixes the 'scheduling while atomic' errors introduced by
commit 12dac075

 ("tg3: adapt tg3 to
use reworked PCI PM code").

The first hunk of the patch removes an unnecessary
tg3_set_power_state() call.  The chip will already be in the D0 state
either due to a chip reset or through a previous call to
tg3_set_power_state().

The second hunk of the patch moves the tg3_set_power_state() call
outside the critical section guarded by tg3_full_lock() and
tg3_full_unlock() functions.  The power state of the device is and
should be outside the lock's domain and all other
tg3_set_power_state() calls support this.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>