spmi: pmic-arb: Support more than 128 peripherals

Add support for more than 128 peripherals by taking a lazy
caching approach to the mapping tables. Instead of reading and
caching the tables at boot given some fixed size, read them and
cache them on an as needed basis. We still assume a max size of
512 peripherals, trading off some space for simplicity.

Based on a patch by Gilad Avidov <gavidov@codeaurora.org> and
Sagar Dharia <sdharia@codeaurora.org>.

Cc: Gilad Avidov <gavidov@codeaurora.org>
Cc: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>