x86: Get rid of ->hard_math and all the FPU asm fu

Reimplement FPU detection code in C and drop old, not-so-recommended
detection method in asm. Move all the relevant stuff into i387.c where
it conceptually belongs. Finally drop cpuinfo_x86.hard_math.

[ hpa: huge thanks to Borislav for taking my original concept patch
  and productizing it ]

[ Boris, note to self: do not use static_cpu_has before alternatives! ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1367244262-29511-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/1365436666-9837-2-git-send-email-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index ada87a3..d6c28ac 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -243,7 +243,7 @@
 	if (!access_ok(VERIFY_WRITE, buf, size))
 		return -EACCES;
 
-	if (!HAVE_HWFP)
+	if (!static_cpu_has(X86_FEATURE_FPU))
 		return fpregs_soft_get(current, NULL, 0,
 			sizeof(struct user_i387_ia32_struct), NULL,
 			(struct _fpstate_ia32 __user *) buf) ? -1 : 1;
@@ -350,11 +350,10 @@
 	if (!used_math() && init_fpu(tsk))
 		return -1;
 
-	if (!HAVE_HWFP) {
+	if (!static_cpu_has(X86_FEATURE_FPU))
 		return fpregs_soft_set(current, NULL,
 				       0, sizeof(struct user_i387_ia32_struct),
 				       NULL, buf) != 0;
-	}
 
 	if (use_xsave()) {
 		struct _fpx_sw_bytes fx_sw_user;