acpi: Output all errors/warnings/remarks when compiling ASL

Remove -va option when invoking IASL compiler so that we can see
errors/warnings/remarks in the build log.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

scripts/Makefile.lib

@@ -326,7 +326,7 @@ $(obj)/%.S: $(src)/%.ttf
 quiet_cmd_acpi_c_asl= ASL     $<
 cmd_acpi_c_asl=         \
 	$(CPP) -x assembler-with-cpp -P $(UBOOTINCLUDE) -o $<.tmp $<; \
-	iasl -p $< -tc -va $<.tmp; \
+	iasl -p $< -tc $<.tmp; \
 	mv $(patsubst %.asl,%.hex,$<) $@
 
 $(obj)/dsdt.c:    $(src)/dsdt.asl