Global cleanup: Fix a few spelling errors

Just a trivial patch to fix a few errors found by codespell.

Here's the command I used:
codespell -S subprojects,out \
-L fwe,dout,tast,crate,parms,claus,nt,nd,te,truns,trun

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I4e3b277f220fa70dcab21912c30f1d26d9bd8749
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/62840
Original-Reviewed-by: Felix Singer <felixsinger@posteo.net>
Original-Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71455
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/ichspi.c b/ichspi.c
index 21f6d9b..1f13b93 100644
--- a/ichspi.c
+++ b/ichspi.c
@@ -980,7 +980,7 @@
 	}
 
 	/* Program offset in flash into FADDR while preserve the reserved bits
-	 * and clearing the 25. address bit which is only useable in hwseq. */
+	 * and clearing the 25. address bit which is only usable in hwseq. */
 	temp32 = REGREAD32(ICH9_REG_FADDR) & ~0x01FFFFFF;
 	REGWRITE32(ICH9_REG_FADDR, (offset & 0x00FFFFFF) | temp32);