Enable the timing.c selftest with MBEDTLS_TIMING_ALT

This caused trouble for users that were using the selftest feature
along with an alternative implementation. They were forced to 
provide their own version of a selftest. Since it was not mentioned
in the define description, it should not be required, and is provided
roughly as it was before breaking changes in 77daaad198 were
introduced.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/timing.c b/library/timing.c
index d4f9554..47e34f9 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -352,9 +352,9 @@
     return 0;
 }
 
+#endif /* !MBEDTLS_TIMING_ALT */
 
 #if defined(MBEDTLS_SELF_TEST)
-
 /*
  * Busy-waits for the given number of milliseconds.
  * Used for testing mbedtls_timing_hardclock.
@@ -383,9 +383,8 @@
             mbedtls_printf(" cycles=%lu ratio=%lu millisecs=%lu secs=%lu hardfail=%d a=%lu b=%lu\n", \
                            cycles, ratio, millisecs, secs, hardfail,   \
                            (unsigned long) a, (unsigned long) b);     \
-            mbedtls_printf(" elapsed(hires)=%lu elapsed(ctx)=%lu status(ctx)=%d\n", \
+            mbedtls_printf(" elapsed(hires)=%lu status(ctx)=%d\n", \
                            mbedtls_timing_get_timer(&hires, 0),      \
-                           mbedtls_timing_get_timer(&ctx.timer, 0),  \
                            mbedtls_timing_get_delay(&ctx));         \
         }                                                               \
         return 1;                                                    \
@@ -526,5 +525,4 @@
 }
 
 #endif /* MBEDTLS_SELF_TEST */
-#endif /* !MBEDTLS_TIMING_ALT */
 #endif /* MBEDTLS_TIMING_C */