cache: remove unused cache function

Author: DacoTaco

libogc/system_asm.S

@@ -300,22 +300,6 @@ __InitSystem:
 	mtlr    r0
 	blr
 
-	.globl __flush_cache
-__flush_cache:
-	lis		r5,0xffff
-	ori		r5,r5,0xfff1
-	and		r5,r5,r3
-	subf	r3,r5,r3
-	add		r4,r4,r3
-1:	dcbst	r0,r5
-	sync
-	icbi	r0,r5
-	addic	r5,r5,8
-	subic.	r4,r4,8
-	bge		1b
-	sync
-	blr
-
 	.globl __reset
 __reset:
 	b		1f