x86/sev: Remove unnecessary GFP_KERNEL_ACCOUNT for temporary variables

Some variables allocated in sev_send_update_data are released when
the function exits, so there is no need to set GFP_KERNEL_ACCOUNT.

Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Link: https://lore.kernel.org/r/20250428063013.62311-1-flyingpeng@tencent.com


Signed-off-by: Sean Christopherson <seanjc@google.com>