treewide: devm_kmalloc() -> devm_kmalloc_array()

The devm_kmalloc() function has a 2-factor argument form,
devm_kmalloc_array(). This patch replaces cases of:

        devm_kmalloc(handle, a * b, gfp)

with:
        devm_kmalloc_array(handle, a * b, gfp)

as well as handling cases of:

        devm_kmalloc(handle, a * b * c, gfp)

with:

        devm_kmalloc(handle, array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        devm_kmalloc_array(handle, array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        devm_kmalloc(handle, 4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

Some manual whitespace fixes were needed in this patch, as Coccinelle
really liked to write "=devm_kmalloc..." instead of "= devm_kmalloc...".

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
expres...