at91: provide macb clks with "pclk" and "hclk" name

The macb driver expects clocks with the names "pclk" and "hclk".  We
currently provide "macb_clk" but to fit in line with other
architectures (namely AVR32), provide "pclk" and a fake "hclk".

Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>