CONFIG_BCM63XX_CPU_6348 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

support 6348 CPU

configname: CONFIG_BCM63XX_CPU_6348

Linux Kernel Configuration
└─>CPU support
└─>support 6348 CPU
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  

depends
CONFIG_BCM63XX