linux-yocto: Add complete Kernel configuration files

Add a complete kernel configuration (defconfig) for the axm5500,
axm5500sim, and elpaso boards for the 3.4 and 3.10 standard and preempt-rt
kernels.

Signed-off-by: Hong H. Pham <hong.pham@windriver.com>

Conflicts:
	recipes-kernel/linux/linux-yocto_3.4.bbappend