[ARM] nwfpe: Add decleration for ExtendedCPDO

Add header file decleration for 'ExtendedCPDO' in fpa11.h
to stop the following sparse warning:

extended_cpdo.c:90:14: warning: symbol 'ExtendedCPDO' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben-linux@fluff.org>