[S390] cleanup psw related bits and pieces

Split out addressing mode bits from PSW_BASE_BITS, rename PSW_BASE_BITS
to PSW_MASK_BASE, get rid of psw_user32_bits, remove unused function
enabled_wait(), introduce PSW_MASK_USER, and drop PSW_MASK_MERGE macros.
Change psw_kernel_bits / psw_user_bits to contain only the bits that
are always set in the respective mode.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 72a1c8d..fd83b69 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -300,9 +300,9 @@
 	_s390_regs_common32 regs32;
 	int err, i;
 
-	regs32.psw.mask = PSW32_MASK_MERGE(psw32_user_bits,
-					   (__u32)(regs->psw.mask >> 32));
-	regs32.psw.addr = PSW32_ADDR_AMODE31 | (__u32) regs->psw.addr;
+	regs32.psw.mask = psw32_user_bits |
+		((__u32)(regs->psw.mask >> 32) & PSW32_MASK_USER);
+	regs32.psw.addr = PSW32_ADDR_AMODE | (__u32) regs->psw.addr;
 	for (i = 0; i < NUM_GPRS; i++)
 		regs32.gprs[i] = (__u32) regs->gprs[i];
 	save_access_regs(current->thread.acrs);
@@ -327,8 +327,8 @@
 	err = __copy_from_user(&regs32, &sregs->regs, sizeof(regs32));
 	if (err)
 		return err;
-	regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
-				        (__u64)regs32.psw.mask << 32);
+	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
+		(__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32;
 	regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
 	for (i = 0; i < NUM_GPRS; i++)
 		regs->gprs[i] = (__u64) regs32.gprs[i];