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_code_O2/osPfsFreeBlocks.c

@@ -13,7 +13,6 @@ s32 osPfsFreeBlocks(OSPfs* pfs, s32* leftoverBytes) {
     if (!(pfs->status & PFS_INITIALIZED)) {
         return (PFS_ERR_INVALID);
     }
-
     if ((ret = __osCheckId(pfs)) != 0) {
         return ret;
     }