This commit changes only ones with the default 2048 and
leaves the others.
E.g. this leaves SYSTEM_RAMTEST_STACKSIZE, whose default is 1024.
I guess those need to be inspected one-by-one.
1.Remove void cast for function because many place ignore the returned value witout cast
2.Replace void cast for variable with UNUSED macro
Change-Id: Ie644129a563244a6397036789c4c3ea83c4e9b09
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>