Blackfin: drop unused irq_panic()/DEBUG_ICACHE_CHECK

This code was useful during early port development when our icache code
wasn't solid, but that ship has sailed long ago, and no code calls this
function anymore (irq_panic).  So punt it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/Kconfig.debug

@@ -102,17 +102,6 @@ config DEBUG_DOUBLEFAULT_RESET
 
 endchoice
 
-config DEBUG_ICACHE_CHECK
-	bool "Check Instruction cache coherency"
-	depends on DEBUG_KERNEL
-	depends on DEBUG_HWERR
-	help
-	  Say Y here if you are getting weird unexplained errors. This will
-	  ensure that icache is what SDRAM says it should be by doing a
-	  byte wise comparison between SDRAM and instruction cache. This
-	  also relocates the irq_panic() function to L1 memory, (which is
-	  un-cached).
-
 config DEBUG_HUNT_FOR_ZERO
 	bool "Catch NULL pointer reads/writes"
 	default y