FS#10048 : enable MMU and data cache on Sansa AMS to give a major speed up

- cache IRAM and DRAM
- map IRAM just next to DRAM to remove the need for -mlong-calls and reduce binsize
- tweak delays in Fuze button code
- tweak delays in Clip button code (down button sometimes doesn't respond anyway : an alternate driver is being worked on)

Before reporting any problem, please check your filesystem or format your player from the OF

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21228 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/as3525/boot.lds

@@ -6,17 +6,11 @@ OUTPUT_FORMAT(elf32-littlearm)
 OUTPUT_ARCH(arm)
 STARTUP(target/arm/crt0.o)
 
-/*
-No need for DRAM in our bootloader
-#define DRAMSIZE (MEMORYSIZE * 0x100000) - TTB_SIZE
-#define DRAMORIG 0x30000000
-*/
 #define IRAMORIG 0x81000000
 #define IRAMSIZE 0x50000
 
 MEMORY
 {
-    /*DRAM : ORIGIN = DRAMORIG, LENGTH = DRAMSIZE*/
     IRAM : ORIGIN = IRAMORIG, LENGTH = IRAMSIZE
 }