[PARISC] Remove the spurious do_softirq calls from entry.S

remove the spurious do_softirq calls from entry.S

With these in we were calling do_softirq twice; plus the calls in
entry.S took no account of nesting.

Signed-off-by: James Bottomley <jejb@parisc-linux.org>

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>