eventdev: remove unneeded dependencies

eventdev: remove unneeded dependencies

Since eventdev uses event structures rather than working directly on
mbufs, there is no actual dependencies on the mbuf library. The
inclusion of an mbuf pointer element inside the event itself does not
require the inclusion of the mbuf header file. Similarly the pci
header is not needed, but following their removal, rte_memory.h is
needed for the definition of the __rte_cache_aligned macro.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>