Documentation/process: Update ARM contact for embargoed hardware issues

With Grant taking a prominent role in Linaro, I will take over as the
process ambassador for ARM w.r.t. embargoed hardware issues.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Grant Likely <grant.likely@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ctmarinas

Documentation/process/embargoed-hardware-issues.rst

@@ -246,7 +246,7 @@ an involved disclosed party. The current ambassadors list:
   ============= ========================================================
   AMD		Tom Lendacky <tom.lendacky@amd.com>
   Ampere	Darren Hart <darren@os.amperecomputing.com>
-  ARM		Grant Likely <grant.likely@arm.com>
+  ARM		Catalin Marinas <catalin.marinas@arm.com>
   IBM Power	Anton Blanchard <anton@linux.ibm.com>
   IBM Z		Christian Borntraeger <borntraeger@de.ibm.com>
   Intel		Tony Luck <tony.luck@intel.com>