[EXT] [PATCH v2] doc: update FIPS docs

[Akhil Goyal]

> Added missing step for converting SHA request files to correct
> format. Replaced AES_GCM with GCM to follow the correct
> naming format.
> 
> Fixes: 3d0fad56b74 ("examples/fips_validation: add crypto FIPS application")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Jakub Poczatek <jakub.poczatek at intel.com>
> Acked-by: Fan Zhang <roy.fan.zhang at intel.com>
Applied to dpdk-next-crypto