hw/sd/sd.c: Drop unused sd_acmd_type[] array

hw/sd/sd.c: Drop unused sd_acmd_type[] array

Drop the sd_acmd_type[] array: it is never used. (The equivalent
sd_cmd_type[] array for normal commands is used to identify
those commands whose argument includes the card address in the
top 16 bits; but for app commands the card address is passed
with the APP_CMD prefix, not with the argument to the app command
itself.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>