Revert "hcrypto: avoid key_type redefinition"

Revert "hcrypto: avoid key_type redefinition"

This reverts commit 81487fcf3ae93d2efea6f0935a0493680b5d3d11.

This change didn't receive sufficient review before it was pushed.
It breaks builds on IRIX, and produces kernel modules that don't
load on a number of other Linux-based systems.

A correct fix for the underlying problem (that both Linux and
hcrypto want to use the "struct key_type" identifier) will follow
this patch.

Change-Id: Ib215f9d8adde75180a86f985052c77600a294895
Reviewed-on: http://gerrit.openafs.org/4191
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>