python: Drop ${PYTHON_PN}

python 2 is gone and we don't need the abstraction now, drop the remaining usage
of this variable.

The definition in python3-dir.bbclass is left for now for other layers.

(From OE-Core rev: b566b1e32c7993d1ab7795562f648e52ce186a70)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3-jinja2_3.1.3.bb

@@ -24,25 +24,25 @@ do_install_ptest() {
 }
 
 RDEPENDS:${PN}-ptest += " \
-    ${PYTHON_PN}-pytest \
-    ${PYTHON_PN}-unittest-automake-output \
-    ${PYTHON_PN}-toml \
-    ${PYTHON_PN}-unixadmin \
+    python3-pytest \
+    python3-unittest-automake-output \
+    python3-toml \
+    python3-unixadmin \
 "
 
 RDEPENDS:${PN} += " \
-    ${PYTHON_PN}-asyncio \
-    ${PYTHON_PN}-crypt \
-    ${PYTHON_PN}-io \
-    ${PYTHON_PN}-json \
-    ${PYTHON_PN}-markupsafe \
-    ${PYTHON_PN}-math \
-    ${PYTHON_PN}-netclient \
-    ${PYTHON_PN}-numbers\
-    ${PYTHON_PN}-pickle \
-    ${PYTHON_PN}-pprint \
-    ${PYTHON_PN}-shell \
-    ${PYTHON_PN}-threading \
+    python3-asyncio \
+    python3-crypt \
+    python3-io \
+    python3-json \
+    python3-markupsafe \
+    python3-math \
+    python3-netclient \
+    python3-numbers\
+    python3-pickle \
+    python3-pprint \
+    python3-shell \
+    python3-threading \
 "
 
 BBCLASSEXTEND = "native nativesdk"