mfd: wcd9xxx-slimslave: Change slim driver to use %pK

Change slimslave driver to use %pK instead
of %p. %pK hides addresses when the users doesn't
have kernel permissions. If address information
is needed echo 0 > /proc/sys/kernel/kptr_restrict.

Change-Id: I319f7a4f71e779963c4d31eb5a0f91637cf805d2
Signed-off-by: Surendar karka <sukark@codeaurora.org>