Update bcc-2.2.0 README with new instruction

bcc-2.2.0/README

+After building the compiler using ubuild.sh it may be necessary to import some 
+files from the binary compiler provided by Gaisler (Version 2.2.0 gcc).
+https://www.gaisler.com/anonftp/bcc2/bin/
+Copy the directory bcc-2.2.0-gcc/sparc-gailser-elf into the destination build 
+directory.
+
 See BCC User's Manual for information on how to build the toolchain and libbcc.
 
 The source code is based on the following commits: