Palmas driver assumes it is always TPS659xx regulator on all DRA7xx based
boards to enable mmc regulator. This is not true always like in case of
DRA71x-evm. So get this information based on the board.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Delete omap4_vmmc_pbias_config from omap_hsmmc.c]
Signed-off-by: Tom Rini <trini@konsulko.com>