wl12xx: change max/default template size

The max template size was increased in the new fw.
However, we should use the max size only when needed, as it
consumes some of the chip's memory.

Thus, by default initialize the templates to the default size.
Initialize to the maximum size only when required.

Use WL1271_CMD_TEMPL_DFLT_SIZE instead of some of the
predefined structs, as some of them didn't account
for additional IEs that might be added to the template.

Delete structs defintions not used after these changes.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>