x86/mm/pkeys: Do not skip PKRU register if debug registers are not used

__show_regs() fails to dump the PKRU state when the debug registers are in
their default state because there is a return statement on the debug
register state.

Change the logic to report PKRU value even when debug registers are in
their default state.

Fixes:c0b17b5b

 ("x86/mm/pkeys: Dump PKRU with other kernel registers")
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20160910183045.4618-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>