Makefile: Minor cscope fixups
Create cscope symbols for assembly files in addition to .c/.h files.
Create cscope database with full path instead of relative path so cscope
can be used with CSCOPE_DB in any directory.
Signed-off-by: Alexandre Raymond <cerbere@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>