MAINTAINERS: Remove the AT91 clk driver entry

I've stopped actively maintaining this driver for quite some time
already, and at91 maintainers are doing a good job at maintaining it.
Remove the AT91 clk driver entry so that the driver automatically
falls under the "ARM/Microchip (AT91) SoC support" entry.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

MAINTAINERS

@@ -1256,11 +1256,6 @@ F:	arch/arm/mach-aspeed/
 F:	arch/arm/boot/dts/aspeed-*
 N:	aspeed
 
-ARM/ATMEL AT91 Clock Support
-M:	Boris Brezillon <boris.brezillon@bootlin.com>
-S:	Maintained
-F:	drivers/clk/at91
-
 ARM/CALXEDA HIGHBANK ARCHITECTURE
 M:	Rob Herring <robh@kernel.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)