Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/arch/arm/mm/proc-arm720.S b/arch/arm/mm/proc-arm720.S
index 665266d..7a06e59 100644
--- a/arch/arm/mm/proc-arm720.S
+++ b/arch/arm/mm/proc-arm720.S
@@ -63,7 +63,7 @@
 /*
  * Function: arm720_proc_do_idle(void)
  * Params  : r0 = unused
- * Purpose : put the processer in proper idle mode
+ * Purpose : put the processor in proper idle mode
  */
 ENTRY(cpu_arm720_do_idle)
 		mov	pc, lr