target/riscv/kvm: turn u32/u64 reg functions into macros

target/riscv/kvm: turn u32/u64 reg functions into macros

This change is motivated by a future change w.r.t CSRs management. We
want to handle them the same way as KVM extensions, i.e. a static array
with KVMCPUConfig objs that will be read/write during init and so on.
But to do that properly we must be able to declare a static array that
hold KVM regs.

C does not allow to init static arrays and use functions as
initializers, e.g. we can't do:

.kvm_reg_id = kvm_riscv_reg_id_ulong(...)

When instantiating the array. We can do that with macros though, so our
goal is turn kvm_riscv_reg_ulong() in a macro. It is cleaner to turn
every other reg_id_*() function in macros, and ulong will end up using
the macros for u32 and u64, so we'll start with them.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20250429124421.223883-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Cc: qemu-stable@nongnu.org
(cherry picked from commit b6096103494506514d9bfa442f62fef36ffc8fba)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>