[ARM] 4189/1: AT91: MACB Ethernet clock

The MACB Ethernet driver searches for a "macb_clk" clock, so rename the
"ether_clk" on the SAM9260 and SAM9263 to "macb_clk".

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>