package/unzip: import patches from Debian

In Buildroot there are multiple way to apply patches on a package [1]

- Adding `.patch` file in the package directory.
- Define `<pkg>_PATCH` variable with the location of the patch tar.gz.
  It used to download Debian patches tarball.
- Implement custom patching logic with `PRE`/`POST` patches hooks.

To make the CycloneDX SBOM generation not dependant on downloading the
packages, the two last options have the downside of not appearing on the
generated SBOM.

The unzip package is downloading a tarball from the Debian mirror with
the `<pkg>_PATCH` method [2].

To improve the tracking of the patched vulnerabilities for the unzip
package this commit import the patches previously downloaded with the
`_PATCH` variable in the Buildroot tree.
This allows to add the `CVE:` trailer [3] on the patches that fix
vulnerabilities to better track which patch is fixing the vulnerability.

[1] https://buildroot.org/downloads/manual/manual.html#patch-policy
[2] https://snapshot.debian.org/archive/debian/20250311T215724Z/pool/main/u/unzip/unzip_6.0-29.debian.tar.xz
[3] 1167d0ff3d docs/manual: mention CVE trailer

Signed-off-by: Thomas Perale <thomas.perale@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

.checkpackageignore

@@ -911,7 +911,6 @@ package/uhttpd/0002-Fix-TCP_FASTOPEN-related-compile-error.patch lib_patch.Upstr
 package/unbound/S70unbound Shellcheck
 package/unifdef/0001-Makefile-fix-error-on-install.patch lib_patch.Upstream
 package/unscd/S46unscd Shellcheck lib_sysv.Indent lib_sysv.Variables
-package/unzip/0001-Add-a-CMakeFile.txt-to-ease-cross-compilation.patch lib_patch.Upstream
 package/upmpdcli/S99upmpdcli Shellcheck lib_sysv.Indent lib_sysv.Variables
 package/urg/0001-select-h.patch lib_patch.Upstream
 package/urg/0002-urg-gcc6-fix-narrowing-conversion.patch lib_patch.Upstream