arm64: dts: qcom: msm8992-bullhead: Fix cont_splash_mem size

Original google firmware reports 12 MiB:
[    0.000000] cma: Found cont_splash_mem@0, memory base 0x0000000003400000, size 12 MiB, limit 0xffffffffffffffff

which is actually 12*1024*1024 = 0xc00000.

This matches the aosp source [1]:
&cont_splash_mem {
	reg = <0 0x03400000 0 0xc00000>;
};

Fixes: 3cb6a27 ("arm64: dts: qcom: msm8992-bullhead: Fix cont_splash_mem mapping")
Fixes: 976d321 ("arm64: dts: qcom: msm8992: Make the DT an overlay on top of 8994")

[1] https://android.googlesource.com/kernel/msm.git/+/android-7.0.0_r0.17/arch/arm64/boot/dts/lge/msm8992-bullhead.dtsi#141

Signed-off-by: Petr Vorel <[email protected]>
Reviewed-by: Konrad Dybcio <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

arch/arm64/boot/dts/qcom/msm8992-lg-bullhead.dtsi

@@ -2,7 +2,7 @@
 /*
  * Copyright (c) 2015, LGE Inc. All rights reserved.
  * Copyright (c) 2016, The Linux Foundation. All rights reserved.
- * Copyright (c) 2021, Petr Vorel <[email protected]>
+ * Copyright (c) 2021-2022, Petr Vorel <[email protected]>
  * Copyright (c) 2022, Dominik Kobinski <[email protected]>
  */
 
@@ -49,7 +49,7 @@
 		};
 
 		cont_splash_mem: memory@3400000 {
-			reg = <0 0x03400000 0 0x1200000>;
+			reg = <0 0x03400000 0 0xc00000>;
 			no-map;
 		};