powerpc: use kernel endianness in MSR in 32-bit signal handler

This mirrors the behavior in handle_rt_signal32, to obey kernel endianness
rather than assume a 32-bit process is big-endian. Without this change,
any 32-bit little-endian process will SIGILL immediately upon handling a
signal.
Signed-off-by: Joseph J Allen <eerykitty@gmail.com>
Signed-off-by: Will Springer <skirmisher@protonmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2058876.irdbgypaU6@sheen

arch/powerpc/kernel/signal_32.c

@@ -929,8 +929,9 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 	regs->gpr[3] = ksig->sig;
 	regs->gpr[4] = (unsigned long) sc;
 	regs->nip = (unsigned long)ksig->ka.sa.sa_handler;
-	/* enter the signal handler in big-endian mode */
+	/* enter the signal handler in native-endian mode */
 	regs->msr &= ~MSR_LE;
+	regs->msr |= (MSR_KERNEL & MSR_LE);
 	return 0;
 
 failed: