KVM: arm64: Add RES1_WHEN_E2Hx constraints as configuration flags

KVM: arm64: Add RES1_WHEN_E2Hx constraints as configuration flags

"Thanks" to VHE, SCTLR_EL2 radically changes shape depending on the
value of HCR_EL2.E2H, as a lot of the bits that didn't have much
meaning with E2H=0 start impacting EL0 with E2H=1.

This has a direct impact on the RESx behaviour of these bits, and
we need a way to express them.

For this purpose, introduce two new constaints that, when the
controlling feature is not present, force the field to RES1 depending
on the value of E2H. Note that RES0 is still implicit,

This allows diverging RESx values depending on the value of E2H,
something that is required by a bunch of SCTLR_EL2 bits.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260202184329.2724080-13-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>