[RFC] arm64: defconfig: enable 48-bit VA by default

[Stuart Yoder]

Catalin/Will,

This is not a patch mean to be applied, but a query about whether there
is any reason to not enable 48-bit VA by default in the arm64 defconfig.

The Freescale LS2085A physical memory map requires 48-bit VA in Linux for the
reasons mentioned in [1].

Based on the comment in [1] by Catalin, it seems that the intent
is to turn this on by default.

Is there any issues anyone sees with a patch that does this:

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 4e17e7e..5acf75d 100644
@@ -47,6 +47,7 @@ CONFIG_ARCH_ZYNQMP=y
 CONFIG_PCI=y
 CONFIG_PCI_MSI=y
 CONFIG_PCI_XGENE=y
+CONFIG_ARM64_VA_BITS_48=y
 CONFIG_SMP=y
 CONFIG_PREEMPT=y
 CONFIG_KSM=y

Thanks,
Stuart

[1] https://www.marc.info/?l=linux-arm-kernel&m=140965303205473&w=1