ddr: altera: Internal rw_mgr_mem_calibrate_vfifo() cleanup part 4

ddr: altera: Internal rw_mgr_mem_calibrate_vfifo() cleanup part 4

This is kind of microseries-within-series indent cleanup.
This patch cleans up the handling of grp_calibrated such
that the variable isn't used all over the place, but just
very localy. This allows trimming down the indent issues.

It is likely that this patch has checkpatch warnings, but
for the sake of not breaking the code, these are ignored.

No functional change.

Signed-off-by: Marek Vasut <marex@denx.de>