soc: qcom: rpmpd: Rename MAX_8996_RPMPD_STATE to MAX_CORNER_RPMPD_STATE

soc: qcom: rpmpd: Rename MAX_8996_RPMPD_STATE to MAX_CORNER_RPMPD_STATE

Older SoCs like MSM8916, MSM8939, MSM8974, MSM8996, ...
use "voltage corners" instead of "voltage levels".
It seems like they all use exactly the same set of corner values,
a value from 0-6 where 6 is the maximum corner (super turbo).

In preparation to add the power domains for MSM8916, rename
MAX_8996_RPMPD_STATE to MAX_CORNER_RPMPD_STATE to make it clear
that this is the max_state to be used for all SoCs using corners.  -

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20200916104135.25085-2-stephan@gerhold.net
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>