ARCv3: Require HAS_LLSC for enabling HAS_ATLD option

Restore the dependency of HAS_ATLD on HAS_LLSC. This commit reverts the
Kconfig changes introduced by commit bc57bd4 ("ARCv3: add new version
of 32-bit arch_atomic_* with atld.<op> instrs").

The implementation of 32-bit atomic functions with atld.<op> instructions
cannot fully replace the LLSC version and cannot be used as a workaround
for the llock/scond livelock issue. Use the ARC_LLSC_BACKOFF option as a
workaround for the llock/scond livelock issue.

The HAS_ATLD option can only be used for efficient fetch-and-operate atomic
functions implementation.

Signed-off-by: Pavel Kozlov <[email protected]>

arch/arc/Kconfig

@@ -434,10 +434,10 @@ config ARC_LLSC_BACKOFF
     depends on ISA_ARCV3 && SMP && ARC_HAS_LLSC
 
 config ARC_HAS_ATLD
-	bool "Insn: ATLD (efficient atomic ops)"
+	bool "Insn: ATLD (efficient fetch-and-operate atomic ops)"
 	default n
 	depends on ISA_ARCV3
-	depends on !ARC_CANT_LLSC
+	depends on ARC_HAS_LLSC
 
 config ARC_HAS_SWAPE
 	bool "Insn: SWAPE (endian-swap)"