Fix a duplicate symbol name.

Both versions of silk/tables_NLSF_CB had symbols
named silk_NLSF_CB1_Wght_Q9 which causes problems
if both files are build as part of the same
compilation unit. Rename the wideband version
to include a 'WB' string to avoid the conflict.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>