efi_loader: use LOGC_EFI consistently

The log category should be LOGC_EFI all over the EFI sub-system.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

lib/efi_loader/efi_net.c

@@ -15,6 +15,8 @@
  * Reset():	 EfiSimpleNetworkInitialized -> EfiSimpleNetworkInitialized
  */
 
+#define LOG_CATEGORY LOGC_EFI
+
 #include <efi_loader.h>
 #include <dm.h>
 #include <linux/sizes.h>