UPSTREAM: base: soc: Handle custom soc information sysfs entries

Soc framework exposed sysfs entries are not sufficient for some
of the h/w platforms. Currently there is no interface where soc
drivers can expose further information about their SoCs via soc
framework. This change address this limitation where clients can
pass their custom entries as attribute group and soc framework
would expose them as sysfs properties.

Bug: 141190076
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1570480662-25252-1-git-send-email-mnalajal@codeaurora.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry-picked from c31e73121f4c1ec45a3e523ac6ce3ce6dafdcec1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ia1c8d697e29052b4503da7c4b30c2c97d3b697f7