clk: at91: sam9x7: Fix gmac_gclk clock definition

clk: at91: sam9x7: Fix gmac_gclk clock definition

According to the datasheet (see link section), table 12.1, instance ID 24
is used for the GMAC generic clock, while instance ID 67 is reserved. Add
the correct gmac_gclk entry at ID 24, aligned with the SoC clock layout,
and remove the old misplaced entry at ID 67.

Link: https://ww1.microchip.com/downloads/aemDocuments/documents/MPU32/ProductDocuments/DataSheets/SAM9X75-SIP-Series-Data-Sheet-DS60001827.pdf
Fixes: 33013b43e271 ("clk: at91: sam9x7: add sam9x7 pmc driver")
Signed-off-by: Mihai Sain <mihai.sain@microchip.com>
Link: https://lore.kernel.org/r/20260309075329.1528-4-mihai.sain@microchip.com
[claudiu.beznea: massaged the patch description]
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>