twl4030_charger: fix another compile error
twl4030_charger: fix another compile error

When CONFIG_CHARGER_TWL4030=y and CONFIG_TWL4030_MADC=m we get a
compile error:

drivers/built-in.o: In function `twl4030_charger_update_current':
twl4030_charger.c:(.text+0x504681): undefined reference to
`twl4030_get_madc_conversion'

Use IS_REACHABLE to fix it.

Cc: NeilBrown <822ec91a7ef82248fd36162ca8ac3283eba70848@brown.name>
Reported-by: Randy Dunlap <6f29df8e90a57f1ba61ffd63b0468c86bb6d3a99@infradead.org>
Signed-off-by: Grazvydas Ignotas <eac34e836c3bc120048c86fead6dd0257a872a9e@gmail.com>
Acked-by: Tony Lindgren <1001e8702733cced254345e193c88aaa47a4f5de@atomide.com>
Signed-off-by: Sebastian Reichel <1ea78bda3cb6d36efdb8fc89aad6555e21b4887e@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs