tests: mem_protect: enlarge heap size of RISCV64

Because k_thread size in RISCV64 is near 512 bytes, (num_of_thread *
256) bytes heap size is not enough. Enlarge heap size in RISCV64
to the (num_of_thread * 1024) bytes like x86_64 and ARM64.

Signed-off-by: Jim Shu <[email protected]>

Author: cwshu

tests/kernel/mem_protect/mem_protect/src/mem_protect.h

@@ -136,7 +136,8 @@ static inline void set_fault_valid(bool valid)
 
 
 
-#if defined(CONFIG_X86_64) || defined(CONFIG_ARM64)
+#if (defined(CONFIG_X86_64) || defined(CONFIG_ARM64) || \
+	(defined(CONFIG_RISCV) && defined(CONFIG_64BIT)))
 #define TEST_HEAP_SIZE	(2 << CONFIG_MAX_THREAD_BYTES) * 1024
 #define MAX_OBJ 512
 #else