[PARISC] OS_ID_LINUX == 0x0006

We were assigned an OS_ID of 0x0006. Consistently use OS_ID_LINUX
instead of using the magic number. Also update the OS_ID_ defines in
asm/pdc.h to reflect this.

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/include/asm-parisc/pdc.h b/include/asm-parisc/pdc.h
index 3d3446e..33bff61 100644
--- a/include/asm-parisc/pdc.h
+++ b/include/asm-parisc/pdc.h
@@ -278,12 +278,11 @@
 /* constants for OS (NVM...) */
 #define OS_ID_NONE		0	/* Undefined OS ID	*/
 #define OS_ID_HPUX		1	/* HP-UX OS		*/
-#define OS_ID_LINUX		OS_ID_HPUX /* just use the same value as hpux */
 #define OS_ID_MPEXL		2	/* MPE XL OS		*/
 #define OS_ID_OSF		3	/* OSF OS		*/
 #define OS_ID_HPRT		4	/* HP-RT OS		*/
 #define OS_ID_NOVEL		5	/* NOVELL OS		*/
-#define OS_ID_NT		6	/* NT OS		*/
+#define OS_ID_LINUX		6	/* Linux		*/
 
 
 /* constants for PDC_CHASSIS */