ARM: OMAP2+: SmartReflex: Create per-opp debugfs node for errminlimit

Remove the global errminlimit debugfs entry and create per-voltage
entries from the data tables.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: J Keerthy <j-keerthy@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>