x86/efi: move common keyring handler functions to new file

[ Upstream commit ad723674 ]

The handlers to add the keys to the .platform keyring and blacklisted
hashes to the .blacklist keyring is common for both the uefi and powerpc
mechanisms of loading the keys/hashes from the firmware.

This patch moves the common code from load_uefi.c to keyring_handler.c

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1573441836-3632-4-git-send-email-nayna@linux.ibm.com


Signed-off-by: Sasha Levin <sashal@kernel.org>