I8K: allow i8k driver to be built on x86_64 systems

Adds #if clause and additional inline assembly so that the driver
builds on x86_64 systems.

Signed-off-by: Bradley Smith <[e-mail]>
Cc: Frank Sorenson <[e-mail]>
Cc: Jeff Garzik <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/i8k.c

···
 	int rc;
 	int eax = regs->eax;
 
+#if defined(CONFIG_X86_64)
+	asm("pushq %%rax\n\t"
+		"movl 0(%%rax),%%edx\n\t"
+		"pushq %%rdx\n\t"
+		"movl 4(%%rax),%%ebx\n\t"
+		"movl 8(%%rax),%%ecx\n\t"
+		"movl 12(%%rax),%%edx\n\t"
+		"movl 16(%%rax),%%esi\n\t"
+		"movl 20(%%rax),%%edi\n\t"
+		"popq %%rax\n\t"
+		"out %%al,$0xb2\n\t"
+		"out %%al,$0x84\n\t"
+		"xchgq %%rax,(%%rsp)\n\t"
+		"movl %%ebx,4(%%rax)\n\t"
+		"movl %%ecx,8(%%rax)\n\t"
+		"movl %%edx,12(%%rax)\n\t"
+		"movl %%esi,16(%%rax)\n\t"
+		"movl %%edi,20(%%rax)\n\t"
+		"popq %%rdx\n\t"
+		"movl %%edx,0(%%rax)\n\t"
+		"lahf\n\t"
+		"shrl $8,%%eax\n\t"
+		"andl $1,%%eax\n"
+		:"=a"(rc)
+		:    "a"(regs)
+		:    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
+#else
 	asm("pushl %%eax\n\t"
 	    "movl 0(%%eax),%%edx\n\t"
 	    "push %%edx\n\t"
···
 	    "andl $1,%%eax\n":"=a"(rc)
 	    :    "a"(regs)
 	    :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
-
+#endif
 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 		return -EINVAL;