parisc: remove dead code from sys_parisc32.c

Unless I'm totally missing something get_fd_set32/set_fd_set32 are
completely unused.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>