crypto: sha256 - Fix some coding style issues

crypto: sha256 - Fix some coding style issues

For some reason after the first 15 steps the last statement of each
step ends with "t1+t2", missing spaces around the "+". This commit
fixes this. This was done with a 's/= t1+t2/= t1 + t2/' to make sure
no functional changes are introduced.

Note the main goal of this is to make lib/sha256.c's sha256_transform
and its helpers identical in formatting too the duplcate implementation
in crypto/sha256_generic.c so that "diff -u" can be used to compare them
to prove that no functional changes are made when further patches in
this series consolidate the 2 implementations into 1.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>