powerpc/powernv: Enable TM without suspend if possible

Some Power9 revisions can run in a mode where TM operates without
suspended state. If we find ourself on a CPU that might be in this
mode, we query OPAL to check, and if so we reenable TM in CPU
features, and enable a new user feature to signal to userspace that we
are in this mode.

We do not enable the "normal" user feature, PPC_FEATURE2_HTM, but we
do enable PPC_FEATURE2_HTM_NOSC because that indicates to userspace
that the kernel will abort transactions on syscall entry, which is
true regardless of the suspend mode.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/opal-api.h

@@ -896,6 +896,8 @@ enum {
 	 */
 	OPAL_REINIT_CPUS_MMU_HASH	= (1 << 2),
 	OPAL_REINIT_CPUS_MMU_RADIX	= (1 << 3),
+
+	OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED = (1 << 4),
 };
 
 typedef struct oppanel_line {