LU-10565 mdc: add __GFP_COLD for back compatible

LU-10565 mdc: add __GFP_COLD for back compatible

The __GFP_COLD has been removed in upstream. Add
it for compatible.

Lustre-change: https://review.whamcloud.com/31028
Lustre-commit: 8b3cb154856623a03b3cb0dc3e3fbce9a693e831

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: I70d0978fa1cdfb9ea22f0b1511a26b28523048b6
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/31200
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>