mmc: renesas_sdhi: populate SCC pointer at the proper place

mmc: renesas_sdhi: populate SCC pointer at the proper place

The SCC pointer is currently filled whenever the SoC is Gen2+. This is
wrong because there is a Gen2-variant without SCC (SDHI_VER_GEN2_SDR50).
We have been lucky because the writes to unintended registers have not
caused problems so far. But further refactoring work exposed the
problem. So, move the pointer initialization to the place where we know
that the SDHI instance supports tuning. And also populate the 'reset'
pointer unconditionally to make sure the interrupt enable register is
always properly set for Gen2+.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20201110142058.36393-4-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>