bonw15: Set battery Rsense to 5

PRS3 is 0.005 Ohms.

However, I am unsure about this change because PRS1 and PRS2 are also
both 0.005 Ohms, but are in *parallel*.

Ref: bonw15 schematics, Charger (Sheet 70)
Signed-off-by: Tim Crawford <tcrawford@system76.com>

src/board/system76/bonw15/board.mk

@@ -31,10 +31,11 @@ CFLAGS+=-DPS2_TOUCHPAD=PS2_3
 CFLAGS+=-DI2C_USBPD=I2C_1
 
 # Set smart charger parameters
+# XXX: PRS1 and PRS2 are in parallel for adapter Rsense?
 CHARGER=oz26786
 CFLAGS+=\
 	-DCHARGER_ADAPTER_RSENSE=5 \
-	-DCHARGER_BATTERY_RSENSE=10 \
+	-DCHARGER_BATTERY_RSENSE=5 \
 	-DCHARGER_CHARGE_CURRENT=3072 \
 	-DCHARGER_CHARGE_VOLTAGE=17400 \
 	-DCHARGER_INPUT_CURRENT=16920