mali: fix section mismatch

Fix a section mismatch between kbase_carveout_mem_reserve and
memblock_alloc_base by adding an __init annotation to
kbase_carveout_mem_reserve.

Change-Id: I348e67530b57325aefd9031574fed5700fee1456
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>