ANDROID: arm64/mm: Add command line option to make ZONE_DMA32 empty

ZONE_DMA32 is enabled by default on android14-6.1, yet it is not
needed for all devices, nor is it desirable to have if not needed. For
instance, if a partner in GKI 1.0 did not use ZONE_DMA32, memory can
be lower for ZONE_NORMAL relative to older targets, such that memory
would run out more quickly in ZONE_NORMAL leading kswapd to be invoked
unnecessarily.

Correspondingly, provide a means of making ZONE_DMA32 empty via the
kernel command line when it is compiled in via CONFIG_ZONE_DMA32.

P.S. The following two patches are squashed into this one,
1. bf96382f ("ANDROID: dma-direct: Make DMA32 disablement work for CONFIG_NUMA")
2. 135406ce ("ANDROID: dma-direct: Document disable_dma32")

Bug: 199917449
Bug: 268587627
Change-Id: I70ec76914b92e518d61a61072f0b3cb41cb28646
Signed-off-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com>
Signed-off-by: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com>
Signed-off-by: Chinwen Chang <chinwen.chang@mediatek.com>