MBEDTLS_STATIC_ASSERT: make it work outside of a function

At the top level, the macro would have had to be used without a following
semicolon (except with permissive compilers that accept spurious semicolons
outside of a function), which is confusing to humans and indenters. Fix
that.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 46e1b37..45e1aa9 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1622,11 +1622,11 @@
 }
 
 MBEDTLS_STATIC_ASSERT((MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE) == 0,
-                      "One or more key attribute flag is listed as both external-only and dual-use")
+                      "One or more key attribute flag is listed as both external-only and dual-use");
 MBEDTLS_STATIC_ASSERT((PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE) == 0,
-                      "One or more key attribute flag is listed as both internal-only and dual-use")
+                      "One or more key attribute flag is listed as both internal-only and dual-use");
 MBEDTLS_STATIC_ASSERT((PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY) == 0,
-                      "One or more key attribute flag is listed as both internal-only and external-only")
+                      "One or more key attribute flag is listed as both internal-only and external-only");
 
 /** Validate that a key policy is internally well-formed.
  *