board: mpfs_icicle: change maintainer to Conor

Padmarao is leaving Microchip soon, and suggested that I should take
over maintaining the Icicle in U-Boot in his stead.

Suggested-by: Padmarao Begari <padmarao.begari@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>