python3-sense-hat: Drop PYTHON_PN

Starting OE core commit b566b1e32c7993d1ab7795562f648e52ce186a70,
we no longer need PYTHON_PN for any abstraction of python2 vs python3.

Signed-off-by: Khem Raj <raj.khem@gmail.com>

dynamic-layers/meta-python/recipes-devtools/python/python3-sense-hat_2.2.0.bb

@@ -18,7 +18,7 @@ DEPENDS += " \
     "
 
 RDEPENDS:${PN} += " \
-    ${PYTHON_PN}-numpy \
-    ${PYTHON_PN}-rtimu \
-    ${PYTHON_PN}-pillow \
+    python3-numpy \
+    python3-rtimu \
+    python3-pillow \
     "