IVGCVSW-2865 add missing include of functional
IVGCVSW-2865 add missing include of functional

Change-Id: Ib110f8fe8b8980ad948d2ca22061e9d020cb33d7
Signed-off-by: Matthew Bentham <286076deec2404ae356dd8bc92f2f71e81044bd4@arm.com>

ARM-software/armnn,ARM-software/armnn,ARM-software/armnn