Update the documentation of mbedtls_psa_ecp_load_representation

Document the new curve_bits parameter.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto_ecp.c b/library/psa_crypto_ecp.c
index d1e1a97..1a8f15e 100644
--- a/library/psa_crypto_ecp.c
+++ b/library/psa_crypto_ecp.c
@@ -80,10 +80,10 @@
         curve_bytes = data_length / 2;
 
         /* Montgomery public keys are represented in compressed format, meaning
-         * their curve_size is equal to the amount of input. */
+         * their curve_bytes is equal to the amount of input. */
 
         /* Private keys are represented in uncompressed private random integer
-         * format, meaning their curve_size is equal to the amount of input. */
+         * format, meaning their curve_bytes is equal to the amount of input. */
     }
 
     if( explicit_bits )