ARM: OMAP4: omap-twl: Fix setting VSEL code for max_voltage

Errata ProDB00121179 says voltage overshoot may occur if
switch from DVS to non-DVS ranges on TWL6032.
 - DVS range VSEL codes     0x01-0x39
 - non-DVS range VSEL codes 0x3A-0x3E

Max_volt settings (1.418V) were converted to VSEL=0x3A.
This VSEL code is in non-DVS range while all other codes
are in DVS range. Thus using this code leads to voltage
overshoot due to errata.
Now max_volt 1.418V is converted to code VSEL=0x39
which corresponds to 1.417960V and is in the safe range.
The voltages higher than 1.418V aren't used for both 6030 and 6032.
Thus replacing VSEL code 0x3A by 0x39 does not impact performance.
If used SMPS_OFFSET=0 (default only for twl6030 es1.0 and
is not used on twl6032) the max voltage of 1.35V is
recalculated to VSEL=0x3A and is not affected by the patch.

Change-Id: I5e992be09899f520c1635fe3c268cbfdedc4caf4
Signed-off-by: Oleg_Kosheliev <oleg.kosheliev@ti.com>