Start using DMA sampling with ADC

The various code used to make DMA-based sampling work.
Tested (except for some non-functional changes to improve code) on
cart, although not extensively or under any real load.

Change-Id: I187066e857e5077cb017f9f371c8eeaf0a2e2d15
diff --git a/motors/fet12/calib_data_60c.csv b/motors/fet12/calib_data_60c.csv
new file mode 100644
index 0000000..eb1bc52
--- /dev/null
+++ b/motors/fet12/calib_data_60c.csv
@@ -0,0 +1,49 @@
+  0,0,60, -14,-18,135, 151,135,156
+  0,0,60, -11,-8,139, 155,142,148
+  0,0,60, -1,2,156, 156,155,155
+  0,0,60, -14,-15,140, 155,138,158
+  0,0,60, -6,-7,143, 155,148,157
+  0,0,60, -16,-15,133, 158,136,156
+  0,0,60, -17,-20,135, 155,134,155
+  0,0,60, -14,-11,138, 149,139,156
+  0,0,60, -19,-15,135, 157,135,152
+  0,0,60, -18,-17,140, 162,141,161
+  0,0,60, -8,-6,149, 157,147,156
+  0,0,60, -3,-6,142, 149,144,155
+  0,0,60, -6,-2,144, 150,145,152
+  0,0,60, -17,-15,138, 155,138,156
+  0,0,60, -11,-8,145, 151,142,156
+  0,0,60, -15,-15,140, 150,136,158
+  0,0,60, -16,-12,145, 156,141,156
+  0,0,60, -20,-17,135, 156,134,159
+  0,0,60, -6,0,151, 149,148,155
+  0,0,60, -17,-14,140, 156,141,156
+  0,0,60, -16,-13,141, 161,146,157
+  0,0,60, -9,-9,150, 159,146,162
+  0,0,60, -16,-13,136, 150,132,150
+  0,0,60, -22,-19,140, 159,140,163
+  0,0,60, -14,-13,140, 155,138,156
+  0,0,60, -14,-15,139, 158,139,158
+  0,0,60, -8,-6,150, 157,150,159
+  0,0,60, -4,0,153, 158,154,156
+  0,0,60, -16,-11,138, 158,140,152
+  0,0,60, -14,-15,138, 156,140,158
+  0,0,60, 6,7,157, 156,158,155
+  0,0,60, -2,-4,150, 151,146,157
+  0,0,60, -15,-14,139, 153,135,154
+  0,0,60, -7,-6,143, 155,146,157
+  0,0,60, -7,-9,144, 156,146,155
+  0,0,60, -10,-8,150, 156,150,162
+  0,0,60, -7,-4,144, 155,147,152
+  0,0,60, -18,-14,143, 158,142,160
+  0,0,60, -10,-10,140, 155,141,154
+  0,0,60, -19,-19,135, 156,135,156
+  0,0,60, -7,-11,140, 151,140,153
+  0,0,60, -3,-6,151, 157,150,158
+  0,0,60, -12,-10,143, 156,141,153
+  0,0,60, -10,-4,148, 155,146,156
+  0,0,60, -12,-9,140, 153,141,151
+  0,0,60, -7,-9,146, 154,148,156
+  0,0,60, -21,-19,137, 160,136,157
+  0,0,60, -20,-21,131, 158,135,154
+  0,0,60, -14,-12,141, 157,141,155