xtensa: xt2000: drop redundant sysmem initialization

sysmem structure initialization in xt2000 platform_init is identical to
the one done in init_arch just before the call to platform_init.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --cc arch/xtensa/platforms/xt2000/setup.c
Simple merge