x86: Add some log categories

Add categories for i8259 and bios files, so that log statements have the
right category.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/lib/i8259.c b/arch/x86/lib/i8259.c
index 465ff70..088f78f 100644
--- a/arch/x86/lib/i8259.c
+++ b/arch/x86/lib/i8259.c
@@ -13,6 +13,8 @@
  * Programmable Interrupt Controllers.
  */
 
+#define LOG_CATEGORY	UCLASS_IRQ
+
 #include <log.h>
 #include <asm/io.h>
 #include <asm/i8259.h>