MAINTAINERS: rectify the INTEL IADX DRIVER entry

MAINTAINERS: rectify the INTEL IADX DRIVER entry

Commit 3b93ca7a124d ("dmaengine: idxd: Init and probe for Intel data
accelerators") added the INTEL IADX DRIVER entry in MAINTAINERS, which
mentions include/linux/idxd.h as file entry. However, this header file was
not added in this commit, nor in any later one.

Hence, since then, ./scripts/get_maintainer.pl --self-test complains:

  warning: no file matches F: include/linux/idxd.h

Drop the file entry to the non-existing file in INTEL IADX DRIVER now.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20200307205737.5829-1-lukas.bulwahn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>