gralloc: Fix issue with mmap/munmap meta due to reserved size

Fix possible security issue which can happen if client changes
reserved size in meta data. This can cause wrong size munmap

Bug:238103940
Change-Id: Ie8c226d9e7d1d0dc481d026ccd454a1db46fb915
Signed-off-by: linjoey <[email protected]>
1 file changed