MIPS: BMIPS: Add PRId for BMIPS5200 (Whirlwind)

This is a dual core (quad thread) BMIPS5000.  It needs a little extra
code to boot the second core (CPU2/CPU3), but for now we can treat it the
same as a single core BMIPS5000.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8166/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/cpu.h

@@ -142,6 +142,7 @@
 #define PRID_IMP_BMIPS3300_BUG	0x0000
 #define PRID_IMP_BMIPS43XX	0xa000
 #define PRID_IMP_BMIPS5000	0x5a00
+#define PRID_IMP_BMIPS5200	0x5b00
 
 #define PRID_REV_BMIPS4380_LO	0x0040
 #define PRID_REV_BMIPS4380_HI	0x006f

arch/mips/kernel/cpu-probe.c

@@ -1087,6 +1087,7 @@ static inline void cpu_probe_broadcom(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	}
 	case PRID_IMP_BMIPS5000:
+	case PRID_IMP_BMIPS5200:
 		c->cputype = CPU_BMIPS5000;
 		__cpu_name[cpu] = "Broadcom BMIPS5000";
 		set_elf_platform(cpu, "bmips5000");