USB: f_fs: Increase the IN endpoint buffer allocation

Some UDC may require allocation of some extra bytes for
TX buffer due to hardware requirement. Add necessary
changes for the same.

Change-Id: I186cfc876f52e694113b895dfc4044948cb1fb2d
Signed-off-by: Sujeet Kumar <ksujeet@codeaurora.org>
Signed-off-by: ChandanaKishori Chiluveru <cchilu@codeaurora.org>
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>