next-cube.c: update scr_ops to properly use modern memory API

next-cube.c: update scr_ops to properly use modern memory API

The old QEMU memory accessors used in the original NextCube patch series had
separate functions for 1, 2 and 4 byte accessors. When the series was finally
merged a simple wrapper function was written to dispatch the memory accesses
using the original functions.

Convert scr_ops to use the memory API directly renaming it to next_scr_ops,
marking it as DEVICE_BIG_ENDIAN, and handling any unaligned accesses.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Message-ID: <20231220131641.592826-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>