Fix these gcc warnings:
arch/dotproductavx.cpp:53:45: warning:
type qualifiers ignored on cast result type [-Wignored-qualifiers]
arch/dotproductavx.cpp:54:45: warning:
type qualifiers ignored on cast result type [-Wignored-qualifiers]
arch/dotproductsse.cpp:59:45: warning:
type qualifiers ignored on cast result type [-Wignored-qualifiers]
arch/dotproductsse.cpp:60:45: warning:
type qualifiers ignored on cast result type [-Wignored-qualifiers]
Signed-off-by: Stefan Weil <sw@weilnetz.de>