[hmac,sival] Test cfg.key_swap

[nasahlpa]

Description

Recently, a HMAC endianness test was added in 4999941. There, different endianness configurations for the messages were tested. However, as Jade pointed out, it also would make sense to test the key endianess swap, which can be configured with the cfg.key_swap configuration register. This test could be added to the existing hmac_endianness_test test.

[rprakas-gsc]

Sure, pascal. I will update the hmac_endianness_test code to add this!