soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler

soc: qcom: rpmh-rsc: Loop over fewer bits in irq handler

readl() returns a u32, and BITS_PER_LONG is different on 32-bit vs.
64-bit architectures. Let's loop over the possible bits set in that type
instead of looping over more bits than we ever may need to.

Cc: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20200521060425.24285-3-swboyd@chromium.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>