docs(intel): add Sieu Mun and Benjamin Jit Loon as maintainers

Add Sieu Mun Tang and Benjamin Jit Loon Lim as new
Intel SocFPGA platform maintainers and remove the
rest of the Intel SocFPGA platform maintainers.

Signed-off-by: Sieu Mun Tang <sieu.mun.tang@intel.com>
Change-Id: Ieb9a35e278d70a12351aaccab90ddc7be09dc861
1 file changed