linux-xlnx: Add support for MicroBlaze 'linux.bin.ub' make target

* Added patch which separates 'linux.bin.ub' from the 'linux.bin'
  MicroBlaze makefile target.

Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>
tune-microblaze: Fix default KERNEL_IMAGETYPE value for microblaze

* Use the proper target 'linux.bin.ub'

Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>
meta-kc705: linux-xlnx: Add "EPOLL" to defconfig

Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>