SPKVDD regulator was being disabled whenever EPDC was included in the
image, because the EPD PMIC initialization code includes an invocation
of regulator_has_full_constraints().  This causes all regulators with
zero ref count to be disabled as part of a late_initcall.  To prevent
this disable (which breaks ethernet and DHCP), set regulator to
have boot_on attribute, so that it will not be disabled at end of
driver loading sequence.

Signed-off-by: Danny Nold <dannynold@freescale.com>