rsa: remove unnecessary check in priv/pub key parsing

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/rsa.c b/library/rsa.c
index b250e1d..c8ea980 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -107,12 +107,9 @@
         return ret;
     }
 
+    /* mbedtls_asn1_get_tag() already ensures that len is valid (i.e. p+len <= end)*/
     end = p + len;
 
-    if (end > (key + keylen)) {
-        return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
-    }
-
     if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
         return ret;
     }
@@ -243,12 +240,9 @@
         return ret;
     }
 
+    /* mbedtls_asn1_get_tag() already ensures that len is valid (i.e. p+len <= end)*/
     end = p + len;
 
-    if (end > (key + keylen)) {
-        return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
-    }
-
     /* Import N */
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
         return ret;