exec.c: Rename cpu_physical_memory_write_rom_internal()

exec.c: Rename cpu_physical_memory_write_rom_internal()

Rename cpu_physical_memory_write_rom_internal() to
address_space_write_rom_internal(), and make it take
MemTxAttrs and return a MemTxResult. This brings its
API into line with address_space_write().

This is an internal function to exec.c; fixing its API
will allow us to change the global function
cpu_physical_memory_write_rom().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20181122133507.30950-2-peter.maydell@linaro.org