This commit addds new code for generating dynamic sai.profile file.
The sai.profile.j2 will generate the sai.profile dynamically based on
the topology. It will generate the sai.profile under /etc/sai.d/ directory
in syncd. Before syncd is started this J2 file will be run from the start.sh
file from /usr/bin/ directory. Since the sai.profile is dynamically generated
the old sai.profile file is not required so deleted the file for S6100.
It also address couple of more changes for port_config.ini support is added
for speed in the file which can be used later to find the port speed. Also
the buffer_default_t*.j2 file the ports should be from 0 to 64 changed.

Unit tested the code on S6100 for dynamic generation of sai.profile file for
both T0 and T1 and the file was created in /etc/sai.d/sai.profile
Similarly tested the sonic binary on S6000 to make sure that the sai.profile is
copied from the /usr/share/sonic/hwsku/sai.profile to /etc/sai.d/sai.profile.

Signed-off-by: Harish Venkatraman <Harish_Venkatraman@dell.com>

Updating the sonic-sairedis point.

Signed-off-by: Harish Venkatraman <Harish_Venkatraman@dell.com>