x86: fix broken math-emu with lazy allocation of fpu area

Fix the math emulation that got broken with the recent lazy allocation of FPU
area. init_fpu() need to be added for the math-emulation path aswell
for the FPU area allocation.

math emulation enabled kernel booted fine with this, in the presence
of "no387 nofxsr" boot param.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: hpa@zytor.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/asm-x86/i387.h

@@ -193,6 +193,8 @@ static inline int restore_i387(struct _fpstate __user *buf)
 
 #else  /* CONFIG_X86_32 */
 
+extern void finit(void);
+
 static inline void tolerant_fwait(void)
 {
 	asm volatile("fnclex ; fwait");