pc-bios/s390-ccw/main: Remove superfluous call to enable_subchannel()

enable_subchannel() is already done during is_dev_possibly_bootable()
(which is called from find_boot_device() -> find_subch()), so there
is no need to do this again in the main() function.

Message-Id: <20200806105349.632-9-thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

pc-bios/s390-ccw/main.c

@@ -280,7 +280,6 @@ int main(void)
     boot_setup();
     if (have_iplb) {
         find_boot_device();
-        enable_subchannel(blk_schid);
         ipl_boot_device();
     } else {
         probe_boot_device();