Fix include path to psa/crypto_spe.h

We can't have a public header or library file reference our test
environment (except possibly under test-only options, and even so, it would
be with great reluctance). This breaks the build for other people.
Fix #8259.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/psa/crypto_platform.h b/include/psa/crypto_platform.h
index 35a42f8..ee41c89 100644
--- a/include/psa/crypto_platform.h
+++ b/include/psa/crypto_platform.h
@@ -83,7 +83,7 @@
  */
 #if defined(MBEDTLS_PSA_CRYPTO_SPM)
 #define PSA_CRYPTO_SECURE 1
-#include "../tests/include/spe/crypto_spe.h"
+#include "crypto_spe.h"
 #endif // MBEDTLS_PSA_CRYPTO_SPM
 
 #if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)