Remove '<' from doxygens above struct element to produce doc properly

Remove '<' from doxygens above struct element to produce doc properly

By the doxygen generation format, for the doxygen above the struct
elements, should be written by the format below:
/** ... */
or
/**
 * ...
 */

Previously, there was '<' in the doxygen comment above the struct
elements. Thus, it is fixed by removing '<'.

Change-Id: I519f7a7f80c1fb1887a6658cf9d72eeb9a593370
Signed-off-by: SangYoun Kwak <sy.kwak@samsung.com>