Simplify negative list expansion

Signed-off-by: Felix Conway <[email protected]>

scripts/mbedtls_framework/bignum_common.py

@@ -74,10 +74,7 @@ def combination_two_lists(first_vals: List[T], second_vals: List[T]) -> List[Tup
 
 def expand_list_negative(values: List[str]) -> List[str]:
     """Adds the negative of every element in the list to the list"""
-    new_list = []
-    for value in values:
-        new_list.extend([value, f"-{value}"])
-    return new_list
+    return values + [f"-{value}" for value in values]
 
 def bits_to_limbs(bits: int, bits_in_limb: int) -> int:
     """ Return the appropriate ammount of limbs needed to store