doc: add MSR_IA32_TSX_CTRL snapshot limitation

Signed-off-by: Nikita Kalyazin <[email protected]>

Author: kalyazin

README.md

@@ -151,6 +151,8 @@ plans, check out our [kernel support policy](docs/kernel-policy.md).
 - The [SendCtrlAltDel](docs/api_requests/actions.md#sendctrlaltdel) API request
   is not supported for aarch64 enabled microVMs.
 - Configuring CPU templates is only supported for Intel enabled microVMs.
+- If a CPU template is not used on x86_64, overwrites of `MSR_IA32_TSX_CTRL` MSR
+  value will not be preserved after restoring from a snapshot.
 - The `pl031` RTC device on aarch64 does not support interrupts, so guest
   programs which use an RTC alarm (e.g. `hwclock`) will not work.