lights: Add LP5562 RGBLED driver

This adds support for the TI LP5562 RGB LED driver.

Things to note:
- The driver is initialized in simple PWM mode using its internal clock,
  for R,G,B, but not for W(hite).
- The chip doesn't have a WHO_AM_I or DEVICE_ID register to check.
  Instead we read the W_CURRENT register that we're generally not using
  and therefore doesn't get changed.
- The current is left at the default 17.5 mA but could be changed using
  the command line argument.

Datasheet:
https://www.ti.com/lit/ds/symlink/lp5562.pdf

Signed-off-by: Julian Oes <julian@oes.ch>

src/drivers/drv_sensor.h

@@ -157,6 +157,8 @@
 #define DRV_LED_DEVTYPE_RGBLED        0x7a
 #define DRV_LED_DEVTYPE_RGBLED_NCP5623C 0x7b
 #define DRV_LED_DEVTYPE_RGBLED_IS31FL3195    0xbf
+#define DRV_LED_DEVTYPE_RGBLED_LP5562    0xc0
+
 #define DRV_BAT_DEVTYPE_SMBUS         0x7c
 #define DRV_SENS_DEVTYPE_IRLOCK       0x7d
 #define DRV_SENS_DEVTYPE_PCF8583      0x7e