Convert CONFIG_E1000_NO_NVM to Kconfig

This converts the following to Kconfig:
   CONFIG_E1000_NO_NVM

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 84d859c..56f9416 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -239,6 +239,10 @@
 
 	  <http://support.intel.com/support/network/adapter/pro100/21397.htm>
 
+config E1000_NO_NVM
+	bool "Intel PRO/1000 has no NVMEM / EEPROM"
+	depends on E1000
+
 config E1000_SPI_GENERIC
 	bool "Allow access to the Intel 8257x SPI bus"
 	depends on E1000