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/libultra_boot_O1/initialize.c

@@ -80,5 +80,5 @@ void __osInitialize_common(void) {
     HW_REG(AI_BITRATE_REG, u32) = 0xf;
 }
 
-void __osInitialize_autodetect() {
+void __osInitialize_autodetect(void) {
 }