[XS] Change in coreboot[main]: Fix no-op for empty arg in Makefile conditional

[Nico Huber (Code Review)]

Attention is currently required from: Ashish Kumar Mishra, Balaji Manigandan, Saurabh Mishra.

Nico Huber has posted comments on this change by Balaji Manigandan. ( https://review.coreboot.org/c/coreboot/+/83887?usp=email )

Change subject: Fix no-op for empty arg in Makefile conditional
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Patch Set 4:

(1 comment)

Patchset:

PS4: 
Sorry, I still can't reproduce this (tried docker ubuntu:24.04).
> Although I hit this issue due to different change, it can be replicated like:

What change?
> $(if ,-$(CBFSTOOL) $@.tmp remove -n $(call extract_nth,2,$(file)) 2>/dev/null)

Makes no difference. And I wouldn't expect any as `$(3)` is empty by default.