tests: drivers: Remove unnessesary include

The nucleo_h7X3zi overlays use memory attributes and therfore the
dedicated include file. This is unnessesary, since the memory attribute
include is already included from the underlaying CPU base file
"stm32h7.dtsi". Remove the unnessesary includes.

Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>