memory: jz4780-nemc: Reduce size of const array

The maximum value found in that array is 15, there's no need to store
these values as uint32_t, a uint8_t is enough.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>