x86/pkeys/selftests: Remove dead debugging code, fix dprint_in_signal

x86/pkeys/selftests: Remove dead debugging code, fix dprint_in_signal

There is some noisy debug code at the end of the signal handler.  It was
disabled by an early, unconditional "return".  However, that return also
hid a dprint_in_signal=0, which kept dprint_in_signal=1 and effectively
locked us into permanent dprint_in_signal=1 behavior.

Remove the return and the dead code, fixing dprint_in_signal.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171342.846B9B2E@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>