qseecom: ARMv8: support qseecom_save_partition_hash

Implementing the ARMv8 version of qseecom_save_partition_hash
by calling scm_call2 with the proper paramaters

Until this change, only the ARMv7 version was implemented
(by calling scm_call) and ARMv8 version was missing

Without this change, ioctl QSEECOM_IOCTL_SAVE_PARTITION_HASH_REQ
fails on ARMv8 platforms and only works on ARMv7

CRs-Fixed: 714330
Change-Id: I855ca847d62a0ffd8dc59207b7ea3a0ac6f79d99
Signed-off-by: Jon Ronen-Drori <jonr@codeaurora.org>