power: supply: Add charger driver for Rockchip RK817

Hello Chris Morgan,

The patch 11cb8da0189b: "power: supply: Add charger driver for Rockchip RK817" from Aug 26, 2022, leads to the following Smatch static checker warning:

	drivers/power/supply/rk817_charger.c:143 rk817_chg_cur_to_reg()
	warn: signedness bug returning '(-22)'

drivers/power/supply/rk817_charger.c

    124 static u8 rk817_chg_cur_to_reg(u32 chg_cur_ma)
               ^^

This is a u8.

    125 {
    126         if (chg_cur_ma >= 3500)
    127                 return CHG_3_5A;
    128         else if (chg_cur_ma >= 3000)
    129                 return CHG_3A;
    130         else if (chg_cur_ma >= 2750)
    131                 return CHG_2_75A;
    132         else if (chg_cur_ma >= 2500)
    133                 return CHG_2_5A;
    134         else if (chg_cur_ma >= 2000)
    135                 return CHG_2A;
    136         else if (chg_cur_ma >= 1500)
    137                 return CHG_1_5A;
    138         else if (chg_cur_ma >= 1000)
    139                 return CHG_1A;
    140         else if (chg_cur_ma >= 500)
    141                 return CHG_0_5A;
    142         else
--> 143                 return -EINVAL;
                        ^^^^^^^^^^^^^^^

Can't return a negative.

    144 }

regards,
dan carpenter