clk: qcom: Specify LE device endianness

All these clock controllers are little endian devices, but so far
we've been relying on the regmap mmio bus handling this for us
without explicitly stating that fact. After commit 4a98da2164cf
(regmap-mmio: Use native endianness for read/write, 2015-10-29),
the regmap mmio bus will read/write with the __raw_*() IO
accessors, instead of using the readl/writel() APIs that do
proper byte swapping for little endian devices.

So if we're running on a big endian processor and haven't
specified the endianness explicitly in the regmap config or in
DT, we're going to switch from doing little endian byte swapping
to big endian accesses without byte swapping, leading to some
confusing results. On my apq8074 dragonboard, this causes the
device to fail to boot as we access the clock controller with
big endian IO accesses even though the device is little endian.

Specify the endianness explicitly so that the regmap core
properly byte swaps the accesses for us.

Reported-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>