[common] Refactor Protected Files, part 2

[dimakuv]

Description of the changes

This commit refactors PF code without changing functionality (part 2 in a series of commits). In particular, this commit simplifies function signatures of ipf_read_node() and ipf_write_node().

Extracted from #1841 at the request of @mkow.

How to test this PR?

N/A.

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This change is 

[mkow]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion, not enough approvals from maintainers (2 more required), not enough approvals from different teams (1 more required, approved so far: Intel) (waiting on @dimakuv)

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common/src/protected_files/protected_files.c line 847 at r1 (raw file):

        // read the root node of the mht
        if (!ipf_read_node(pf, /*node_number=*/1, &pf->root_mht.encrypted.cipher))
			return false;

tabs

[dimakuv]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion, not enough approvals from maintainers (2 more required), not enough approvals from different teams (1 more required, approved so far: Intel), "fixup! " found in commit messages' one-liners (waiting on @mkow)

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common/src/protected_files/protected_files.c line 847 at r1 (raw file):

Previously, mkow (Michał Kowalczyk) wrote…

tabs

Done. I wonder how this could happen.

[mkow]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: all files reviewed, all discussions resolved, not enough approvals from maintainers (1 more required), "fixup! " found in commit messages' one-liners

[kailun-qin]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: all files reviewed, all discussions resolved, "fixup! " found in commit messages' one-liners

[kailun-qin]

Reviewed 1 of 1 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved