net: ena: cosmetic: extract code to ena_indirection_table_set()

Extract code to ena_indirection_table_set() to make
the code cleaner.

Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>