dma/idxd: fix AVX2 in non-datapath functions

dma/idxd: fix AVX2 in non-datapath functions

While all systems which will use the idxd driver for hardware will
support AVX2, if the driver is present the initialization functions e.g.
to register logs, will be called on all systems - irrespective of HW
support. This can cause issues if the system running DPDK does not have
AVX2, and the compiler has included AVX instructions in the
initialization code.

To fix this, remove AVX2 instruction set from the whole build of the
driver. Instead, we add "target(avx2)" attribute to all datapath
functions, so those - and only those functions - will having AVX2
instructions in them.

Bugzilla ID: 1038
Fixes: 3d36a0a1c7de ("dma/idxd: add data path job submission")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Conor Walsh <conor.walsh@intel.com>