This is expected behavior, it's an architecture-dependent feature. Embedded Linux doesn't provide this info, most likely because the CPUs don't.
Here's an example from a router of mine:
system type : Atheros AR7161 rev 2 machine : NETGEAR WNDR3700/WNDR3800/WNDRMAC processor : 0 cpu model : MIPS 24Kc V7.4 BogoMIPS : 452.19 wait instruction : yes microsecond timers : yes tlb_entries : 16 extra interrupt vector : yes hardware watchpoint : yes, count: 4, address/irw mask: [0x0000, 0x0f98, 0x0f78, 0x0df8] ASEs implemented : mips16 shadow register sets : 1 kscratch registers : 0 core : 0 VCED exceptions : not available VCEI exceptions : not available