rsa: remove leftovers from mbedtls_rsa_parse_[pub]key()

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/rsa.c b/library/rsa.c
index 2c33869..da32659 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -112,8 +112,6 @@
         return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
     }
 
-    end = p + len;
-
     if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
         return ret;
     }
@@ -248,8 +246,6 @@
         return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
     }
 
-    end = p + len;
-
     /* Import N */
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
         return ret;