[NVME] PMRCAP-Persistent Memory Region Capabilities
This register indicates capabilities of the Persistent Memory Region（持久内存区域）
If the controller does not support the Persistent Memory Region feature, then this register shall be cleared to 0h
| Bits | Type | Reset | Description |
| 31:25 | RO | 0h | Reserved |
| 24 | RO | Impl Spec | Controller Memory Space Supported (CMSS) 1:this bit indicates that addresses supplied by the host are permitted to reference the Persistent Memory Region only if the host has enabled the Persistent Memory Region’s controller memory space (只有当主机已经启用了持久内存区域的控制器内存空间时，主机提供的地址才被允许引用持久内存区域) (如果控制器本身支持使用主机提供的地址来引用持久内存区域，那么 CMSS 位应该被设置为‘1')< |