target_ulong is target-specific, while vaddr isn't.

Remove the unnecessary "exec/cpu-defs.h" target-speficic header
from "memory_mapping.h" and use the target-agnostic "hw/core/cpu.h"
locally in memory_mapping.c.

Remove "exec/memory.h" since MemoryRegion is forward-declared in
"qemu/typedefs.h".

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220207075426.81934-6-f4bug@amsat.org>