Linux 5.16 compat: restore FSR and FSAVE

Commit 3b52ccd introduced a flaw where FSR and FSAVE are not restored
when using a Linux 5.16 kernel.  These instructions are only used when
XSAVE is not supported by the processor meaning only some systems will
encounter this issue.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Attila Fülöp <attila@fueloep.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13210
Closes #13236

include/os/linux/kernel/linux/simd_x86.h

@@ -420,9 +420,9 @@ kfpu_end(void)
 	if (static_cpu_has(X86_FEATURE_XSAVE)) {
 		kfpu_do_xrstor("xrstor", &state->xsave, ~0);
 	} else if (static_cpu_has(X86_FEATURE_FXSR)) {
-		kfpu_save_fxsr(&state->fxsave);
+		kfpu_restore_fxsr(&state->fxsave);
 	} else {
-		kfpu_save_fsave(&state->fsave);
+		kfpu_restore_fsave(&state->fsave);
 	}
 out:
 	local_irq_enable();