[barefoot] Fix y_profile_set to not reset link (#6238)

Y* profile is the name pattern for p4 programs that developed for the current platform. The difference between them is features enabled and resource reservation.

For this platform, it is expected to work on any Y profile. but after the latest changes, the first Y profile is always used.

device/barefoot/x86_64-accton_as9516_32d-r0/syncd.conf

@@ -7,12 +7,18 @@ y_profile_set() {
         return
     fi
 
+    if [[ $(readlink /opt/bfn/install) =~ "install_y"  ]]; then
+        echo "/opt/bfn/install is a link to Y profile"
+        return
+    fi
+
     Y_PROFILE=$(ls -d /opt/bfn/install_y*_profile 2> /dev/null | head -1)
     if [[ -z $Y_PROFILE  ]]; then
         echo "No P4 profile found for Newport"
         return
     fi
 
+    echo "Link /opt/bfn/install to $Y_PROFILE"
     ln -srfn $Y_PROFILE /opt/bfn/install
 }