bootutil/crypto: Move BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE into common

BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE is a universal define
that should be moved into a common area of the header
instead of repeating it for every abstraction that needs it

Signed-off-by: Antonio de Angelis <Antonio.deAngelis@arm.com>
Change-Id: I21e7511218d0dafac8b7337715932c6564d7c3a1
diff --git a/boot/bootutil/include/bootutil/crypto/ecdsa.h b/boot/bootutil/include/bootutil/crypto/ecdsa.h
index b0729ee..3268280 100644
--- a/boot/bootutil/include/bootutil/crypto/ecdsa.h
+++ b/boot/bootutil/include/bootutil/crypto/ecdsa.h
@@ -41,12 +41,10 @@
 #if defined(MCUBOOT_USE_TINYCRYPT)
     #include <tinycrypt/ecc_dsa.h>
     #include <tinycrypt/constants.h>
-    #define BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE (4 * 8)
 #endif /* MCUBOOT_USE_TINYCRYPT */
 
 #if defined(MCUBOOT_USE_CC310)
     #include <cc310_glue.h>
-    #define BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE (4 * 8)
 #endif /* MCUBOOT_USE_CC310 */
 
 #if defined(MCUBOOT_USE_PSA_CRYPTO)
@@ -54,7 +52,6 @@
     #include <string.h>
 #elif defined(MCUBOOT_USE_MBED_TLS)
     #include <mbedtls/ecdsa.h>
-    #define BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE (4 * 8)
     /* Indicate to the caller that the verify function needs the raw ASN.1
      * signature, not a decoded one. */
     #define MCUBOOT_ECDSA_NEED_ASN1_SIG
@@ -65,6 +62,9 @@
 #define NUM_ECC_BYTES (256 / 8)
 #endif
 
+/* Universal defines */
+#define BOOTUTIL_CRYPTO_ECDSA_P256_HASH_SIZE (32)
+
 #include "mbedtls/oid.h"
 #include "mbedtls/asn1.h"
 #include "bootutil/sign_key.h"