s390/vdso: fix clock_gettime for CLOCK_THREAD_CPUTIME_ID, -2 and -3

Git commit 8d8f2e18a6dbd3d09dd918788422e6ac8c878e96
"s390/vdso: ectg gettime support for CLOCK_THREAD_CPUTIME_ID"
broke clock_gettime for CLOCK_THREAD_CPUTIME_ID.

Git commit c742b31c
"fast vdso implementation for CLOCK_THREAD_CPUTIME_ID"
introduced the ECTG for clock id -2. Correct would have been
clock id -3.

Fix the whole mess, CLOCK_THREAD_CPUTIME_ID is based on
CPUCLOCK_SCHED and can not be speed up by the vdso. A speedup
is only available for clock id -3 which is CPUCLOCK_VIRT for
the task currently running on the CPU.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/vdso64/clock_gettime.S

@@ -25,9 +25,7 @@ __kernel_clock_gettime:
 	je	4f
 	cghi	%r2,__CLOCK_REALTIME
 	je	5f
-	cghi	%r2,__CLOCK_THREAD_CPUTIME_ID
-	je	9f
-	cghi	%r2,-2		/* Per-thread CPUCLOCK with PID=0, VIRT=1 */
+	cghi	%r2,-3		/* Per-thread CPUCLOCK with PID=0, VIRT=1 */
 	je	9f
 	cghi	%r2,__CLOCK_MONOTONIC_COARSE
 	je	3f
@@ -106,7 +104,7 @@ __kernel_clock_gettime:
 	aghi	%r15,16
 	br	%r14
 
-	/* CLOCK_THREAD_CPUTIME_ID for this thread */
+	/* CPUCLOCK_VIRT for this thread */
 9:	icm	%r0,15,__VDSO_ECTG_OK(%r5)
 	jz	12f
 	ear	%r2,%a4