Fixes issue with uncart freezing when starting up

-There seemed to have been a problem with caching and uncart, at least
under a9lh and with one system. Explicitly disabling the mpu before
setting it up and before calling subroutines related to setting it up
appears to have fixed the problem.

source/start.s

@@ -99,12 +99,16 @@ _setup_heap:
     ldr r1, =__end__ @ grab the location of the end of the binary
     add r0, r0, r1
     ldr r1, =fake_heap_end @ heap goes from end of program to this variable
-	str r0, [r1]
-	mov pc, lr
+    str r0, [r1]
+    mov pc, lr
 
 _init:
     push {r0-r12, lr}
 
+    mrc p15, 0, r4, c1, c0, 0
+    bic r4, r4, #(1<<0)        @ mpu disable
+    mcr p15, 0, r4, c1, c0, 0
+
     bl _enable_caches
 
     bl _fix_sdmc_mount