arm64: dts: qcom: sdm636-xiaomi-tulip: enable fan53526 buck regulator for LDDR4

[M0Rf30]

From what I've found this regulator is in lavender, clover and tulip schematics.

dmesg:

[   24.306635] fan53555-regulator 1-0060: FAN53555 Option[8] Rev[1] Detected!
[   24.306887] fan53555-reg: Bringing 618750uV into 1000000-1000000uV

i2c-detect:

xiaomi-tulip:~$ sudo i2cdetect -r 1
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-1 using receive byte commands.
I will probe address range 0x08-0x77.
Continue? [Y/n] y
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

[minlexx]

Does linux need to know anything about this regulator though? if DDR was not powered, nothing would work, no? maybe primary BL already sets it up? Especially if this regulator is always-on 🤔

[minlexx]

Also I thought, this is the power to DDR - https://elixir.bootlin.com/linux/v6.11.7/source/arch/arm64/boot/dts/qcom/sdm630-sony-xperia-nile.dtsi#L541

		/* This gives power to the LPDDR4: never turn it off! */
		vreg_l13a_1p8: l13 {

or maybe it can be device specific 🤔