pstore/blk: trivial typo fixes

[ Upstream commit 542243af7182efaeaf6d0f4643f7de437541a9af ]

Fix trivial typos in comments.

Fixes: 2a03ddbd ("pstore/blk: Move verify_size() macro out of function")
Fixes: 17639f67 ("pstore/blk: Introduce backend for block devices")
Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
Link: https://lore.kernel.org/r/20250101111921.850406-1-eugen.hristev@linaro.org


Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>