core: mbedtls: use SHA-1 crypto accelerated routines

Uses the recently provided accelerated SHA-1 routine.

Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/include/mbedtls_config_kernel.h b/lib/libmbedtls/include/mbedtls_config_kernel.h
index 2cb6124..9b68e4c 100644
--- a/lib/libmbedtls/include/mbedtls_config_kernel.h
+++ b/lib/libmbedtls/include/mbedtls_config_kernel.h
@@ -23,6 +23,9 @@
 #if defined(CFG_CRYPTO_SHA1)
 #define MBEDTLS_SHA1_C
 #define MBEDTLS_MD_C
+#if defined(CFG_CORE_CRYPTO_SHA1_ACCEL)
+#define MBEDTLS_SHA1_PROCESS_ALT
+#endif
 #endif
 
 #if defined(CFG_CRYPTO_SHA224) || defined(CFG_CRYPTO_SHA256)