Convert CONFIG_AT91SAM9260 et al to Kconfig

This converts the following to Kconfig:
   CONFIG_AT91SAM9260
   CONFIG_AT91SAM9G20
   CONFIG_AT91SAM9XE
   CONFIG_AT91SAM9261
   CONFIG_AT91SAM9263
   CONFIG_AT91SAM9G45
   CONFIG_AT91SAM9M10G45
   CONFIG_AT91SAM9N12
   CONFIG_AT91SAM9RL
   CONFIG_AT91SAM9X5
   CONFIG_SAM9X60
   CONFIG_SAMA7G5
   CONFIG_SAMA5D2
   CONFIG_SAMA5D3
   CONFIG_SAMA5D4

These options are already select'd as needed, so we're just cleaning up
files here.

Cc: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/at91sam9263ek_norflash_boot_defconfig b/configs/at91sam9263ek_norflash_boot_defconfig
index 4eb24a8..aeb189d 100644
--- a/configs/at91sam9263ek_norflash_boot_defconfig
+++ b/configs/at91sam9263ek_norflash_boot_defconfig
@@ -15,7 +15,7 @@
 CONFIG_DEBUG_UART_CLOCK=100000000
 CONFIG_DEBUG_UART=y
 CONFIG_SYS_LOAD_ADDR=0x22000000
-CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9263,SYS_USE_BOOT_NORFLASH"
+CONFIG_SYS_EXTRA_OPTIONS="SYS_USE_BOOT_NORFLASH"
 CONFIG_BOOTDELAY=3
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 # CONFIG_DISPLAY_BOARDINFO is not set