Fix the epca driver to permit epca_setup() to be invoked from the kernel cmdline

Fix the epca driver to call epca_setup() if digiepca=xxx is included on the
command line and the epca driver is built in.

epca_setup() used to be called from init/main.c in 2.2 kernels, but somewhere
along the way that call was removed but not replaced.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>