plat: imx8mm: cleanup platform.mk

cleanup XLAT and STACK defines
the OCRAM size for ATF is big enough for i.MX 8mm
there is no need to move code to OCRAM_S

Signed-off-by: Silvano di Ninno <silvano.dininno@nxp.com>
Acked-by: Jacky Bai <ping.bai@nxp.com>
(cherry picked from commit b21783f0968e2c17de59956d8bb59dd7ca133b7c)
1 file changed