Fix most compiler warnings in the boot and code segments (#674)

* Less warnings in boot & code segments

* few more warnings gone

* Ran formatter

* z_view warning gone

* -> 1

* f31 -> 31

* Remove function casts

* Few more small improvements

* Separate declaration and assignment in func_80091738 and Item_Give

Co-authored-by: Thar0 <maximilianc64@gmail.com>

src/code/shrink_window.c

@@ -3,11 +3,9 @@
 s32 D_8012CED0 = 0;
 
 s32 sShrinkWindowVal = 0;
-
 s32 sShrinkWindowCurrentVal = 0;
 
 void ShrinkWindow_SetVal(s32 value) {
-
     if (HREG(80) == 0x13 && HREG(81) == 1) {
         osSyncPrintf("shrink_window_setval(%d)\n", value);
     }