Makefile: mrproper should remove *.pyc files

*.pyc files contain compiled Python bytecode. 'make mrproper' should remove
them.

Removing *.pyc files helps for instance sometimes when running into an
error "binman: Unknown entry type 'blob' in node '/binman/blob'".

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/Makefile b/Makefile
index 60ae53d..ac0b888 100644
--- a/Makefile
+++ b/Makefile
@@ -1875,7 +1875,7 @@
 	$(call cmd,rmfiles)
 	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
-		-o -name '*.ko.*' -o -name '*.su' \
+		-o -name '*.ko.*' -o -name '*.su' -o -name '*.pyc' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.symtypes' -o -name 'modules.order' \