Remove customization of and update xz.

I updated the recipe to use newest the raw xz upstream source and
cleaned out my recipes and rebuilt. I have detected no problems.
Not having to have customizations will make it easier to upgrade
int the future as new versions are released.

Signed-off-by: Wren Turkal <wt@penguintechs.org>

recipes/xz/recipe.toml

 [source]
-tar = "https://codeload.github.com/xz-mirror/xz/tar.gz/v5.2.3"
-patches = [
-    "01-no-poll.patch",
-    "02-o_noctty.patch",
-    "03-no-signals.patch"
-]
-script = """
-./autogen.sh
-chmod +w build-aux/config.sub
-wget -O build-aux/config.sub http://git.savannah.gnu.org/cgit/config.git/plain/config.sub
-"""
+tar = "https://codeload.github.com/xz-mirror/xz/tar.gz/v5.2.5"
 
 [build]
 template = "custom"