MAINTAINERS: Remove bouncing irdma maintainer

This maintainer's email no longer works. Remove it from MAINTAINERS.

This still leaves one maintainer for the driver.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Cc: linux-rdma@vger.kernel.org
Link: https://patch.msgid.link/20250808175601.EF0AF767@davehans-spike.ostc.intel.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: hansendc

MAINTAINERS

@@ -12280,7 +12280,6 @@ F:	include/linux/avf/virtchnl.h
 F:	include/linux/net/intel/*/
 
 INTEL ETHERNET PROTOCOL DRIVER FOR RDMA
-M:	Mustafa Ismail <mustafa.ismail@intel.com>
 M:	Tatyana Nikolova <tatyana.e.nikolova@intel.com>
 L:	linux-rdma@vger.kernel.org
 S:	Supported