selftests/bpf: Enable non-arena load-acquire/store-release selftests for riscv64

For riscv64, enable all BPF_{LOAD_ACQ,STORE_REL} selftests except the
arena_atomics/* ones (not guarded behind CAN_USE_LOAD_ACQ_STORE_REL),
since arena access is not yet supported.

Acked-by: Björn Töpel <[email protected]>
Reviewed-by: Pu Lehui <[email protected]>
Tested-by: Björn Töpel <[email protected]> # QEMU/RVA23
Signed-off-by: Peilin Ye <[email protected]>
Link: https://lore.kernel.org/r/9d878fa99a72626208a8eed3c04c4140caf77fda.1746588351.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: peilin-ye

tools/testing/selftests/bpf/progs/bpf_misc.h

@@ -225,8 +225,9 @@
 #define CAN_USE_BPF_ST
 #endif
 
-#if __clang_major__ >= 18 && defined(ENABLE_ATOMICS_TESTS) && \
-	(defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86))
+#if __clang_major__ >= 18 && defined(ENABLE_ATOMICS_TESTS) &&		\
+	(defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) ||	\
+	 (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64))
 #define CAN_USE_LOAD_ACQ_STORE_REL
 #endif