qseecom: Copy userspace buffer into kernel space before dereferencing

ION memory is used for user space to kernel space data passing.
This is directly accessible in kernel. But, if the IOCTL is called
from user space without using User space library, then data might
be pointing to some other memory location, in which case, it would
not be possible to dereference this location in kernel & hence it
would be accessing invalid memory.

Change-Id: Ic50c76ee8b2a696dbb786fce3a68cdc782e15268
Signed-off-by: Hariprasad Dhalinarasimha <hnamgund@codeaurora.org>