ice: sizeof(<type>) should be avoided

With sizeof(), it is preferable to use the variable of type <type> instead
of sizeof(<type>).

There are multiple places where a temporary variable is used to hold a
'size' value which is then used for a subsequent alloc/memset. Get rid
of the temporary variable by calculating size as part of the alloc/memset
statement.

Also remove unnecessary type-cast.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>