RISC-V: KVM: Factor-out VCPU config into separate sources

RISC-V: KVM: Factor-out VCPU config into separate sources

The VCPU config deals with hideleg, hedeleg, henvcfg, and hstateenX
CSR configuration for each VCPU. Factor-out VCPU config into separate
sources so that VCPU config can do things differently for guest HS-mode
and guest VS/VU-mode.

Signed-off-by: Anup Patel <anup.patel@oss.qualcomm.com>
Reviewed-by: Radim Krčmář <radim.krcmar@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260120080013.2153519-9-anup.patel@oss.qualcomm.com
Signed-off-by: Anup Patel <anup@brainfault.org>