[PATCH] powerpc/cell spidernet bogus rx interrupt bit

The current receive interrupt mask sets a bogus bit that doesn't even
belong to the definition of this register. Remove it.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: James K Lewis <jklewis@us.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>