net: ena: Fix Kconfig dependency on X86

BugLink: http://bugs.launchpad.net/bugs/1798182

The Kconfig limitation of X86 is to too wide.
The ENA driver only requires a little endian dependency.

Change the dependency to be on little endian CPU.
Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 8c590f97 linux-next)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/net/ethernet/amazon/Kconfig

@@ -17,7 +17,7 @@ if NET_VENDOR_AMAZON
 
 config ENA_ETHERNET
 	tristate "Elastic Network Adapter (ENA) support"
-	depends on (PCI_MSI && X86)
+	depends on PCI_MSI && !CPU_BIG_ENDIAN
 	---help---
 	  This driver supports Elastic Network Adapter (ENA)"