ubifs: Use U-Boot assert() from <log.h> in UBI/UBIFS code

U-Boot already provides assert function, so it use also in ubi and ubifs code.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index 2c2faaf..9c8ce51 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -27,13 +27,8 @@
 	}                                                                    \
 } while (0)
 #else
-#define ubi_assert(expr)  do {                                               \
-	if (unlikely(!(expr))) {                                             \
-		pr_debug("UBI assert failed in %s at %u\n",                  \
-		       __func__, __LINE__);                                  \
-		dump_stack();                                                \
-	}                                                                    \
-} while (0)
+#include <log.h>
+#define ubi_assert(expr) assert(expr)
 #endif
 
 #define ubi_dbg_print_hex_dump(ps, pt, r, g, b, len, a)                      \