mx6: ddr: add routine to return DDR calibration data

Add routine mmdc_read_calibration() to return the output of DDR
calibration. This can be used for debugging or to aid in construction
of static memory configuration.

This routine will be used in a subsequent patch set adding a virtual
"mx6memcal" board, but could also be useful when gathering statistics
during an initial production run.

Signed-off-by: Eric Nelson <eric@nelint.com>
diff --git a/arch/arm/include/asm/arch-mx6/mx6-ddr.h b/arch/arm/include/asm/arch-mx6/mx6-ddr.h
index cd5bc97..12454fa 100644
--- a/arch/arm/include/asm/arch-mx6/mx6-ddr.h
+++ b/arch/arm/include/asm/arch-mx6/mx6-ddr.h
@@ -461,6 +461,8 @@
 #if defined(CONFIG_MX6QDL) || defined(CONFIG_MX6Q) || defined(CONFIG_MX6D)
 int mmdc_do_write_level_calibration(struct mx6_ddr_sysinfo const *sysinfo);
 int mmdc_do_dqs_calibration(struct mx6_ddr_sysinfo const *sysinfo);
+void mmdc_read_calibration(struct mx6_ddr_sysinfo const *sysinfo,
+                           struct mx6_mmdc_calibration *calib);
 #endif
 
 /* configure mx6 mmdc registers */