[TXYZ] update ENA driver to version 1.2.0k

[Kamal Mostafa]

BugLink: http://bugs.launchpad.net/bugs/1701575

Pull requests for [TXYZ] updating the Amazon ENA network driver to the
latest upstream version (1.2.0k).

All cherry-picks from mainline and net-next, touching only the ENA driver --
except that Trusty needs one additional lib commit from from mainline (a
simple context backport):

 T--- 3464452 lib: devres: add a helper function for ioremap_wc
 
 ---Z b1669c9 net/ena: use napi_complete_done() return value
 TXYZ 90a6c99 net: ena: remove superfluous check in ena_remove()
 --YZ da6f4cf net/ena: switch to pci_alloc_irq_vectors
 TXYZ a77c1aa net: ena: fix rare uncompleted admin command false alarm
 ---Z 418df30 net: ena: fix bug that might cause hang after consecutive open/close interface.
 TXYZ 2d2c600 net: ena: add missing return when ena_com_get_io_handlers() fails
 TXYZ 661d2b0 net: ena: fix race condition between submit and completion admin command
 TXYZ 0857d92 net: ena: add missing unmap bars on device removal
 TXYZ a3af7c1 net: ena: fix theoretical Rx hang on low memory systems
 TXYZ a2cc519 net: ena: disable admin msix while working in polling mode
 TXYZ 800c55c net: ena: bug fix in lost tx packets detection mechanism
 TXYZ e7ff7ef net: ena: update ena driver to version 1.1.7
 TXYZ d149763 net: ena: change return value for unsupported features unsupported return value
 TXYZ 82ef30f net: ena: add hardware hints capability to the driver
 TXYZ 9175011 net: ena: change sizeof() argument to be the type pointer
 TXYZ e2eed0e net: ena: add reset reason for each device FLR
 TXYZ ad974ba net: ena: add support for out of order rx buffers refill
 --YZ 0644368 net: ena: allow the driver to work with small number of msix vectors
 -XYZ e745daf net: ena: use napi_schedule_irqoff when possible
 TXYZ 4265114 net: ena: separate skb allocation to dedicated function
 TXYZ 3ae5907 net: ena: use lower_32_bits()/upper_32_bits() to split dma address
 TXYZ 11a9a46 net: ena: update driver's rx drop statistics
 TXYZ 8523899 net: ena: update ena driver to version 1.2.0