Add comment to make it clear that several SoC are supported by
this generic entry.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
        select HAVE_FB_ATMEL
        select HAVE_NET_MACB
        select HAVE_AT91_DBGU0
+       help
+         Select this if you are using one of Atmel's AT91SAM9x5 family SoC.
+         This means that your SAM9 name finishes with a '5' (except if it is
+         AT91SAM9G45!).
+         This support covers AT91SAM9G15, AT91SAM9G25, AT91SAM9X25, AT91SAM9G35
+         and AT91SAM9X35.
 
 config ARCH_AT91X40
        bool "AT91x40"