x86: Fix cpu detection shift error

That's an ancient bug, from back when this code was in kern/init.c (not
kern/src/init.c either!).

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>

kern/arch/x86/cpuinfo.c

diff --git a/kern/arch/x86/cpuinfo.c b/kern/arch/x86/cpuinfo.c
index b857ee2..cbd8e21 100644
--- a/kern/arch/x86/cpuinfo.c
+++ b/kern/arch/x86/cpuinfo.c
@@ -62,7 +62,7 @@
 	max_extd_lvl = eax;
 	cpuid(1, 0x0, &eax, &ebx, &ecx, &edx);
 	family = ((eax & 0x0FF00000) >> 20) + ((eax & 0x00000F00) >> 8);
-	model = ((eax & 0x000F0000) >> 12) + ((eax & 0x000000F0) >> 4);
+	model = ((eax & 0x000F0000) >> 16) + ((eax & 0x000000F0) >> 4);
 	cprintf("Family: %d\n", family);
 	cprintf("Model: %d\n", model);
 	cprintf("Stepping: %d\n", eax & 0x0000000F);