Revert "panic: Add board ID to panic output"

This reverts commit 4e09c51018.

I checked for the usage of this debug helper in AOSP common kernels as
well as vendor kernels (e.g exynos, msm, mediatek, omap, tegra, x86,
x86_64) hosted at https://android.googlesource.com/kernel/ and I found
out that other than few fairly obsolete Omap trees (for tuna & Glass)
and Exynos tree (for Manta), there is no active user of this debug
helper. So we can safely remove this helper code.

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

include/linux/kernel.h

@@ -830,8 +830,4 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 	 /* OTHER_WRITABLE?  Generally considered a bad idea. */		\
 	 BUILD_BUG_ON_ZERO((perms) & 2) +					\
 	 (perms))
-
-/* To identify board information in panic logs, set this */
-extern char *mach_panic_string;
-
 #endif

kernel/panic.c

@@ -28,9 +28,6 @@
 #define PANIC_TIMER_STEP 100
 #define PANIC_BLINK_SPD 18
 
-/* Machine specific panic information string */
-char *mach_panic_string;
-
 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
 static unsigned long tainted_mask;
 static int pause_on_oops;
@@ -416,11 +413,6 @@ late_initcall(init_oops_id);
 void print_oops_end_marker(void)
 {
 	init_oops_id();
-
-	if (mach_panic_string)
-		printk(KERN_WARNING "Board Information: %s\n",
-		       mach_panic_string);
-
 	pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
 }