ramips: fix mt7621 SoC detection

Signed-off-by: John Crispin <[email protected]>

target/linux/ramips/patches-4.4/0105-set_mt7621_soc_type.patch

@@ -0,0 +1,11 @@
+--- a/arch/mips/ralink/mt7621.c
++++ b/arch/mips/ralink/mt7621.c
+@@ -180,7 +180,7 @@
+ 	} else {
+ 		panic("mt7621: unknown SoC, n0:%08x n1:%08x\n", n0, n1);
+ 	}
+-
++	ralink_soc = MT762X_SOC_MT7621AT;
+ 	rev = __raw_readl(sysc + SYSC_REG_CHIP_REV);
+ 
+ 	snprintf(soc_info->sys_type, RAMIPS_SYS_TYPE_LEN,