MAINTAINERS: adjust file entry in ROHM BD71828 CHARGER

MAINTAINERS: adjust file entry in ROHM BD71828 CHARGER

Commit 5bff79dad20a ("power: supply: Add bd718(15/28/78) charger driver")
adds the file bd71828-power.c in drivers/power/supply/, whereas commit
b838cecc2291 ("MAINTAINERS: Add entry for BD71828 charger") from the same
patch series, adds a section referring to the non-existing file
bd71828-charger.c in the directory above.

Adjust the file entry to refer to the intended existing file.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://patch.msgid.link/20251107123621.425633-1-lukas.bulwahn@redhat.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>