arm64: mte: change PR_MTE_TCF_NONE back into an unsigned long

This constant was previously an unsigned long, but was changed
into an int in commit 433c38f4 ("arm64: mte: change ASYNC and
SYNC TCF settings into bitfields"). This ended up causing spurious
unsigned-signed comparison warnings in expressions such as:

(x & PR_MTE_TCF_MASK) != PR_MTE_TCF_NONE

Therefore, change it back into an unsigned long to silence these
warnings.

Link: https://linux-review.googlesource.com/id/I07a72310db30227a5b7d789d0b817d78b657c639Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://lore.kernel.org/r/20211105230829.2254790-1-pcc@google.comSigned-off-by: Will Deacon <will@kernel.org>

include/uapi/linux/prctl.h

@@ -235,7 +235,7 @@ struct prctl_mm_map {
 #define PR_GET_TAGGED_ADDR_CTRL		56
 # define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
 /* MTE tag check fault modes */
-# define PR_MTE_TCF_NONE		0
+# define PR_MTE_TCF_NONE		0UL
 # define PR_MTE_TCF_SYNC		(1UL << 1)
 # define PR_MTE_TCF_ASYNC		(1UL << 2)
 # define PR_MTE_TCF_MASK		(PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC)

tools/include/uapi/linux/prctl.h

@@ -235,7 +235,7 @@ struct prctl_mm_map {
 #define PR_GET_TAGGED_ADDR_CTRL		56
 # define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
 /* MTE tag check fault modes */
-# define PR_MTE_TCF_NONE		0
+# define PR_MTE_TCF_NONE		0UL
 # define PR_MTE_TCF_SYNC		(1UL << 1)
 # define PR_MTE_TCF_ASYNC		(1UL << 2)
 # define PR_MTE_TCF_MASK		(PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC)