xen: move patches specific for 4.10

Makes it easier to include 4.15 patches later.

pkgs/applications/virtualization/xen/4.10.nix

···
     "-Wno-error=zero-length-bounds"
   ];
 
+  patches = [
+    ./0000-fix-ipxe-src.4.10.patch
+    ./0000-fix-install-python.4.10.patch
+    ./0004-makefile-use-efi-ld.4.10.patch
+    ./0005-makefile-fix-efi-mountdir-use.4.10.patch
+  ];
+
   postPatch = ''
     # Avoid a glibc >= 2.25 deprecation warnings that get fatal via -Werror.
     sed 1i'#include <sys/sysmacros.h>' \

pkgs/applications/virtualization/xen/generic.nix

···
   '';
 
   patches = [
-    ./0000-fix-ipxe-src.patch
-    ./0000-fix-install-python.patch
-    ./0004-makefile-use-efi-ld.patch
-    ./0005-makefile-fix-efi-mountdir-use.patch
   ] ++ (config.patches or []);
 
   postPatch = ''