[AVR32] Drop support for redundant "keepinitrd" boot-time parm.

Given the existing "retain_initrd" boot-time parameter defined in
init/initramfs.c, there appears to be no need for the equivalent
"keepinitrd" parameter.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

arch/avr32/mm/init.c

@@ -224,19 +224,9 @@ void free_initmem(void)
 
 #ifdef CONFIG_BLK_DEV_INITRD
 
-static int keep_initrd;
-
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-	if (!keep_initrd)
 	free_area(start, end, "initrd");
 }
 
-static int __init keepinitrd_setup(char *__unused)
-{
-	keep_initrd = 1;
-	return 1;
-}
-
-__setup("keepinitrd", keepinitrd_setup);
 #endif