aosp_trout_arm64.mk: Pick up BOARD_VENDOR_RAMDISK_KERNEL_MODULES_DIR cmdline

Linux kernel modules in the dir will be used to populate vendor_boot
ramdisk.

Bug: 225304945
Test: Set the variable and build. Check that modules propagated to the
vendor ramdisk

Change-Id: Ia0805c7ebeeedbdf75d5e1120bb3721a74674e2c
1 file changed