riscv: Fix setting no-map in reserved memory nodes

riscv: Fix setting no-map in reserved memory nodes

The no-map property is wrongly skipped if a no-map reserved memory
node follows one without that property. Fix this by not remembering
the absence of a no-map property across loop iterations.

Fixes: 3811ef0c390d ("riscv: Provide a mechanism to fix DT for reserved memory")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>