Improve naming of mimimum RSA key size generation configurations

Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index ab3837e..28249d3 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -3691,9 +3691,6 @@
 //#define MBEDTLS_ECP_WINDOW_SIZE            4 /**< Maximum window size used */
 //#define MBEDTLS_ECP_FIXED_POINT_OPTIM      1 /**< Enable fixed-point speed-up */
 
-/* RSA OPTIONS */
-//#define MBEDTLS_RSA_MIN_KEY_SIZE           1024 /**<  Minimum RSA key size allowed in bits (Minimum possible value is 128 bits) */
-
 /* Entropy options */
 //#define MBEDTLS_ENTROPY_MAX_SOURCES                20 /**< Maximum number of sources supported */
 //#define MBEDTLS_ENTROPY_MAX_GATHER                128 /**< Maximum amount requested from entropy sources */
@@ -3784,6 +3781,9 @@
  */
 //#define MBEDTLS_PSA_KEY_SLOT_COUNT 32
 
+/* RSA OPTIONS */
+#define MBEDTLS_RSA_GEN_KEY_MIN_BITS            1024 /**<  Minimum RSA key size that can be generated in bits (Minimum possible value is 128 bits) */
+
 /* SSL Cache options */
 //#define MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT       86400 /**< 1 day  */
 //#define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50 /**< Maximum entries in cache */
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 8045e6b..69f3981 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -85,8 +85,10 @@
 // Regular implementation
 //
 
-#if !defined(MBEDTLS_RSA_MIN_KEY_SIZE)
-#define MBEDTLS_RSA_MIN_KEY_SIZE 1024
+#if !defined(MBEDTLS_RSA_GEN_KEY_MIN_BITS)
+#define MBEDTLS_RSA_GEN_KEY_MIN_BITS 1024
+#elif MBEDTLS_RSA_GEN_KEY_MIN_BITS < 128
+#error "MBEDTLS_RSA_GEN_KEY_MIN_BITS must be at least 128 bits"
 #endif
 
 /**