regulator: pbias: Add PBIAS regulator for proper voltage switching on MMC1

In the TI SOCs a PBIAS cell exists to provide a bias voltage to the MMC1
IO cells. Without this bias voltage these I/O cells can not function
properly. The PBIAS cell is controlled by software.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 18fb870..6c149a9 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -18,5 +18,6 @@
 obj-$(CONFIG_DM_REGULATOR_SANDBOX) += sandbox.o
 obj-$(CONFIG_REGULATOR_TPS65090) += tps65090_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_PALMAS) += palmas_regulator.o
+obj-$(CONFIG_$(SPL_)DM_REGULATOR_PBIAS) += pbias_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_LP873X) += lp873x_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_LP87565) += lp87565_regulator.o