armv8: LS1043ARDB: Enable PPA in Secure boot defconfig

Enable PPA in secure boot by defining FSL_LS_PPA macro in its
defconfig file.

Signed-off-by: Vinitha Pillai <vinitha.pillai@nxp.com>
Signed-off-by: Sumit Garg <sumit.garg@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>