platform/common/amd64.nix: omit --fmap when writing the entire chip

Trying to write to a chip using --fmap will fail if the chip does
not yet have a valid fmap table (for example, a blank chip).  Let's
omit this flag when writing the entire image.

src/platform/common/amd64.nix

@@ -28,7 +28,7 @@
         else "--fmap-file ${final.fmap}";
       flashromScript = moreFlags: ''
         set -euo pipefail
-        ${final.flashrom}/bin/flashrom -p internal ${layoutFlags} ${moreFlags}
+        ${final.flashrom}/bin/flashrom -p internal $@ ${moreFlags}
       '';
       flashromWriteScript = moreFlags:
         flashromScript "-w ${final.coreboot}/coreboot.rom ${moreFlags}";
@@ -38,8 +38,8 @@
       '';
     in prev.scripts // {
       flashrom = flashromScript "$@";
-      flash-write-fallback = flashromWriteScript "-i FALLBACK";
-      flash-write-normal = flashromWriteScript "-i NORMAL";
+      flash-write-fallback = flashromWriteScript "${layoutFlags} -i FALLBACK";
+      flash-write-normal = flashromWriteScript "${layoutFlags} -i NORMAL";
       flash-write-all = flashromWriteScript "";
       nextboot-use-fallback = nvramToolScript "-w boot_option=Fallback";
       nextboot-use-normal = nvramToolScript "-w boot_option=Normal";