Improve documents about ms_time

And fix typo error

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index ec6581d..e8e60d6 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -3617,7 +3617,7 @@
 //#define MBEDTLS_PLATFORM_VSNPRINTF_MACRO    vsnprintf /**< Default vsnprintf macro to use, can be undefined */
 //#define MBEDTLS_PLATFORM_NV_SEED_READ_MACRO   mbedtls_platform_std_nv_seed_read /**< Default nv_seed_read function to use, can be undefined */
 //#define MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO  mbedtls_platform_std_nv_seed_write /**< Default nv_seed_write function to use, can be undefined */
-//#define MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO   int64_t /**< Default millionseconds time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled. It MUST be signed 64bit integer at least */
+//#define MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO   int64_t //#define MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO   int64_t /**< Default milliseconds time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled. It MUST be at least 30 bits signed integer. */
 //#define MBEDTLS_PRINTF_MS_TIME    PRId64 /**< Default fmt for printf. That's avoid compiler warning if mbedtls_ms_time_t is redefined */
 
 /** \def MBEDTLS_CHECK_RETURN