kernel: x86/sev: Make enc_dec_hypercall() accept a size instead of npages

In the Linux kernel, the following vulnerability has been resolved: x86/sev: Make encdechypercall accept a size instead of npages encdechypercall accepted a page count instead of a size, which forced its callers to round up. As a result, non-page aligned vaddrs caused pages to be spuriously marke...