Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/arch/mips/math-emu/dp_fsp.c b/arch/mips/math-emu/dp_fsp.c
index 1dfbd92..daed683 100644
--- a/arch/mips/math-emu/dp_fsp.c
+++ b/arch/mips/math-emu/dp_fsp.c
@@ -62,7 +62,7 @@
 		break;
 	}
 
-	/* CANT possibly overflow,underflow, or need rounding
+	/* CAN'T possibly overflow,underflow, or need rounding
 	 */
 
 	/* drop the hidden bit */