KVM: PPC: Book3S HV: Use accessors for VCPU registers

KVM: PPC: Book3S HV: Use accessors for VCPU registers

[ Upstream commit ebc88ea7a6ad0ea349df9c765357d3aa4e662aa9 ]

Introduce accessor generator macros for Book3S HV VCPU registers. Use
the accessor functions to replace direct accesses to this registers.

This will be important later for Nested APIv2 support which requires
additional functionality for accessing and modifying VCPU state.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230914030600.16993-7-jniethe5@gmail.com
Stable-dep-of: ecd10702baae ("KVM: PPC: Book3S HV: Handle pending exceptions on guest entry with MSR_EE")
Signed-off-by: Sasha Levin <sashal@kernel.org>