You can define your own title page and add the missing information wherever you want it to go. In the following example, I added it after the author:
\documentclass{beamer}
\usetheme[microtype,faculty=fsps]{fibeamer}
\author{Karthik}
\title{Title of the document}
\date{8.10.2017}
\institute{My institute}
\makeatletter
\setbeamertemplate{title page}{%
% This is slide 0
\setcounter{framenumber}{0}
% Input the university logo
\begin{tikzpicture}[
remember picture,
overlay,
xshift=0.5\fibeamer@lengths@logowidth,
yshift=0.5\fibeamer@lengths@logoheight
]
\node at (0,0) {
\fibeamer@includeLogo[
width=\fibeamer@lengths@logowidth,
height=\fibeamer@lengths@logoheight
]};
\end{tikzpicture}
% Input the title
\usebeamerfont{title}%
\usebeamercolor[fg]{title}%
\begin{minipage}[b][2\baselineskip][b]{\textwidth}%
\raggedright\inserttitle
\end{minipage}
\vskip-.5\baselineskip
% Input the dashed line
\begin{pgfpicture}
\pgfsetlinewidth{2pt}
\pgfsetroundcap
\pgfsetdash{{0pt}{4pt}}{0cm}
\pgfpathmoveto{\pgfpoint{0mm}{0mm}}
\pgfpathlineto{\pgfpoint{\textwidth}{0mm}}
\pgfusepath{stroke}
\end{pgfpicture}
\vfill
% Input the subtitle
\usebeamerfont{subtitle}%
\usebeamercolor[fg]{subtitle}%
\begin{minipage}{\textwidth}
\raggedright%
\insertsubtitle%
\end{minipage}\vskip.25\baselineskip
% Input the author's name
\usebeamerfont{author}%
\usebeamercolor[fg]{author}%
\begin{minipage}{\textwidth}
\raggedright%
\insertauthor\newline%
\insertinstitute\newline%
\insertdate%
\end{minipage}%
}
\makeatother
\begin{document}
\maketitle
\end{document}
