xilinx: zynqmp: Disable LMB for mini u-boot

LMB is not required for mini u-boot which runs out of on chip memory.
Disable CONFIG_LMB from mini u-boot defconfig's.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/45fad28825f0f236ad45e700aca1f39afbb22236.1659691195.git.michal.simek@amd.com