USB: fix hcd interrupt disabling

Commit de85422b, 'USB: fix interrupt
disabling for HCDs with shared interrupt handlers' changed usb_add_hcd()
to strip IRQF_DISABLED from irqflags prior to calling request_irq()
with the justification that such a removal was necessary for shared
interrupts to work properly.  Unfortunately, the change in that commit
unconditionally removes the IRQF_DISABLED flag, causing problems on
platforms that don't use a shared interrupt but require IRQF_DISABLED.
This change adds a check for IRQF_SHARED prior to removing the
IRQF_DISABLED flag.

Fixes the PS3 system startup hang reported with recent Fedora and
OpenSUSE kernels.

Note that this problem is hidden when CONFIG_LOCKDEP=y (ps3_defconfig),
as local_irq_enable_in_hardirq() is defined as a null statement for
that config.

CC: stable <stable@kernel.org>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Stefan Becker <Stefan.Becker@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -1876,7 +1876,8 @@ int usb_add_hcd(struct usb_hcd *hcd,
 		 * with IRQF_SHARED. As usb_hcd_irq() will always disable
 		 * interrupts we can remove it here.
 		 */
-		irqflags &= ~IRQF_DISABLED;
+		if (irqflags & IRQF_SHARED)
+			irqflags &= ~IRQF_DISABLED;
 
 		snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
 				hcd->driver->description, hcd->self.busnum);