`sensors` not reporting values from regulators on the `front_io` bus

[Aaron-Hartwig]

$ pfexec humility sensors -t voltage
humility: attached to 1fc9:143:LERC35Y30MGJ1 via CMSIS-DAP
NAME                 KIND                  VALUE UNPWR   ERR MSSNG UNAVL TMOUT
...
V3P3_SYS_A2          voltage                   -     0     0     0     0     0
V3P3_QSFP0_A0        voltage                   -     0     0     0     0     0
V3P3_QSFP1_A0        voltage                   -     0     0     0     0     0

[Aaron-Hartwig]

Everything validates

$ pfexec humility validate
humility: attached to 1fc9:143:LERC35Y30MGJ1 via CMSIS-DAP
ID VALIDATION   C P  MUX ADDR DEVICE        DESCRIPTION
...
33 validated    2 F  -   0x50 at24csw080    Front IO board FRUID
34 validated    2 F  -   0x73 pca9538       Front IO GPIO expander
35 validated    2 F  -   0x0a pca9956b      Front IO LED driver (left)
36 validated    2 F  -   0x0b pca9956b      Front IO LED driver (right)
37 validated    2 F  -   0x1b tps546b24a    Front IO V3P3_SYS_A2 rail
38 validated    2 F  -   0x19 tps546b24a    Front IO V3P3_QSFP0_A0 rail
39 validated    2 F  -   0x1a tps546b24a    Front IO V3P3_QSFP1_A0 rail