update ZFS to 2.1.2

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/src/submodules/zfsonlinux b/src/submodules/zfsonlinux
index 6150fbe67f7a9485eaabbca7df9a66852cda6892..af88d47f1ee86fae4abcfe0dabca67ea3c94d377 160000 (submodule)
--- a/src/submodules/zfsonlinux
+++ b/src/submodules/zfsonlinux
@@ -1 +1 @@
-Subproject commit 6150fbe67f7a9485eaabbca7df9a66852cda6892
+Subproject commit af88d47f1ee86fae4abcfe0dabca67ea3c94d377