Don't ignore crypto_shash_* return values in IMA and EVM

[robertosassu]

IMA:
https://marc.info/?l=linux-integrity&m=177149412521837&w=2

EVM:
https://marc.info/?l=linux-integrity&m=177034852425579&w=2

The patches have been reviewed by me.

[robertosassu]

Test successful:
https://github.com/robertosassu/ima-evm-utils-upstream/actions/runs/22178843367

[mimizohar]

The IMA patch is queued. The EVM patch has a couple of lines that go beyond 80 chars. I've asked Daniel Hodges to fix them.