The hgatp.VMID mask defines are used before shifting when extracting
VMID value from hgatp CSR value so based on the convention followed
in the other parts of asm/csr.h, the hgatp.VMID mask defines should
not have a _MASK suffix.

While we are here, let's use GENMASK() for hgatp.VMID and hgatp.PPN.
Signed-off-by: NAnup Patel <apatel@ventanamicro.com>
Reviewed-by: NAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: NAtish Patra <atishp@rivosinc.com>
Signed-off-by: NAnup Patel <anup@brainfault.org>