CONFIG_PS3_FLASH is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

PS3 FLASH ROM Storage Driver

modulename: ps3flash.ko

configname: CONFIG_PS3_FLASH

Linux Kernel Configuration
└─>PS3 Platform Options
└─>PS3 FLASH ROM Storage Driver
In linux kernel since version 2.6.23 (release Date: 2007-10-09)  
Include support for the PS3 FLASH ROM Storage.

This support is required to access the PS3 FLASH ROM, which
contains the boot loader and some boot options.
In general, all users will say Y or M.

As this driver needs a fixed buffer of 256 KiB of memory, it can
be disabled on the kernel command line using "ps3flash=off", to
not allocate this fixed buffer.

source code: