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>
diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
index 112775d..5a754c9 100644
--- a/lib/efi_loader/efi_firmware.c
+++ b/lib/efi_loader/efi_firmware.c
@@ -6,6 +6,8 @@
  *			Author: AKASHI Takahiro
  */
 
+#define LOG_CATEGORY LOGC_EFI
+
 #include <charset.h>
 #include <dfu.h>
 #include <efi_loader.h>