Move SHA1_VALIDATE[_RET] outside of MBEDTLS_SHA1_ALT guard

Somehow, mbedtls_sha1_ret() is defined even if MBEDTLS_SHA1_ALT
is set, and it is using SHA1_VALIDATE_RET. The documentation should
be enhanced to indicate that MBEDTLS_SHA1_ALT does _not_ replace
the entire module, but only the core SHA-1 functions.

library/sha1.c

@@ -46,6 +46,11 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST */
 
+#define SHA1_VALIDATE_RET(cond)                             \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_SHA1_BAD_INPUT_DATA )
+
+#define SHA1_VALIDATE(cond)  MBEDTLS_INTERNAL_VALIDATE( cond )
+
 #if !defined(MBEDTLS_SHA1_ALT)
 
 /*
@@ -71,11 +76,6 @@
 }
 #endif
 
-#define SHA1_VALIDATE_RET(cond)                             \
-    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_SHA1_BAD_INPUT_DATA )
-
-#define SHA1_VALIDATE(cond)  MBEDTLS_INTERNAL_VALIDATE( cond )
-
 void mbedtls_sha1_init( mbedtls_sha1_context *ctx )
 {
     SHA1_VALIDATE( ctx != NULL );