igb_uio: remove device reset in release

igb_uio: remove device reset in release

More error reported for device reset in release() [1],
when device pass-through to the guest, host kernel crash on guest exit.

Removing the reset completely.

This is close to reverting commit b58eedfc7dd5 [2], taking into account
previous fix to remove reset in open as well [3], but not exactly same.

With latest code, interrupts are enabled in uio open() callback and
disabled in uio release() callback, so when a DPDK application exit
device interrupts are disabled. Previously interrupts were only enabled
once in igb_uio module insert and disabled in module removal.

Also with latest code device set as bus master in open() and master
cleared in release(), clearing bus master should prevent further DMA
which was one of the target of the initial patch.

The initial intention was also to reset the device to be sure it has
been left in proper state, but currently that part is missing because of
reported problem(s).

Still igb_uio should be safer comparing to the pre b58eedfc7dd5 state.

[1]
http://dpdk.org/ml/archives/dev/2017-November/081459.html

[2]
b58eedfc7dd5 ("igb_uio: issue FLR during open and release of device file")

[3]
f73b38e9245d ("igb_uio: remove device reset in open")

Fixes: e3a64deae2d5 ("igb_uio: prevent reset for bnx2x devices")
Fixes: b58eedfc7dd5 ("igb_uio: issue FLR during open and release of device file")
Cc: stable@dpdk.org
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>