arm64: process: Do not dump memory around register

The addresses stored in registers might not be owned
by the current VM, even though they are mapped.
To avoid stage 2 faults while accessing these regions,
remove displaying of contents around addresses stored
in registers and only show data around sp, lr, pc.

Change-Id: I1cc1deb9d7d9bbfb564fad8fbd89c114ea8a4543
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>