soc/mediatek/mt8192: pmic: update initial setting

We found that the switch frequency of vgpu is at 4~5Mhz with high
current case (> 3.5A) and is at 2.5Mhz with low current case(< 2.8A).
The switch frequency of vgpu should be kept at 2.5Mhz.

The root cause is that phase config of vcore is not disabled, it will
affect the switch frequency of vgpu. Corret the phase setting at
initialization.

BUG=b:172636735
BRANCH=none
TEST=boot asurada correctly

Signed-off-by: Hsin-Hsiung Wang <hsin-hsiung.wang@mediatek.com>
Change-Id: I48d3729302de9e3343dce79fe6f5ed045d0296a5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49005
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/mediatek/mt8192/mt6359p.c b/src/soc/mediatek/mt8192/mt6359p.c
index a8e93ca..68af6f2 100644
--- a/src/soc/mediatek/mt8192/mt6359p.c
+++ b/src/soc/mediatek/mt8192/mt6359p.c
@@ -90,6 +90,7 @@
 	{0x19AE, 0x6E, 0x7E, 0},
 	{0x19B0, 0x3C00, 0x3C00, 0},
 	{0x19B4, 0x20FD, 0xFFFF, 0},
+	{0x19DE, 0x1, 0x1, 6},		/* RG_VGPUVCORE_PH2_OFF, disable phase 2 */
 	{0x1A08, 0x4200, 0x4680, 0},
 	{0x1A0A, 0x6E, 0x7E, 0},
 	{0x1A0C, 0x3C00, 0x3C00, 0},