fs: Add noinline to reduce core_sys_select stack size

Maximum stack size for arm32 devices is (configured by FRAME_WARN)
1024. Core_sys_select()'s stacksize (=1208) exceeds this limit.

Adding noinline attribute to reduce stack size.

Change-Id: I7dbbc99987baf57c91241f6972996541bec0a2c2
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>