powerpc/syscall: Calling kuap_save_and_lock() is wrong

kuap_save_and_lock() is only for interrupts inside kernel.

system call are only from user, calling kuap_save_and_lock()
is wrong.

Fixes: c1672883 ("powerpc/32: Manage KUAP in C")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/332773775cf24a422105dee2d383fb8f04589045.1620302182.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/interrupt.c

@@ -34,9 +34,6 @@ notrace long system_call_exception(long r3, long r4, long r5,
 	syscall_fn f;
 
 	kuep_lock();
-#ifdef CONFIG_PPC32
-	kuap_save_and_lock(regs);
-#endif
 
 	regs->orig_gpr3 = r3;