x86/fpu: Update stale variable name in comment

When the fpu code was reworked pcntxt_mask was renamed to
xfeatures_mask. Reflect it in the comment as well.

Signed-off-by: Cyrill Gorcunov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: cyrillos

arch/x86/kernel/fpu/xstate.c

@@ -840,7 +840,7 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
 
 	/*
 	 * We should not ever be requesting features that we
-	 * have not enabled.  Remember that pcntxt_mask is
+	 * have not enabled.  Remember that xfeatures_mask is
 	 * what we write to the XCR0 register.
 	 */
 	WARN_ONCE(!(xfeatures_mask & BIT_ULL(xfeature_nr)),