tg3: Break out RSS indir table init and assignment

tg3: Break out RSS indir table init and assignment

This patch creates a new device member to hold the RSS indirection table
and separates out the code that initializes the table from the code that
programs the table into device registers.

(cherry picked from commit bcebcc468a6bcd3820fe9ad36b34220563efc93a)
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Jin <joe.jin@oracle.com>