ARM: 9125/1: fix incorrect use of get_kernel_nofault()

Commit 344179f ("ARM: 9106/1: traps: use get_kernel_nofault instead
of set_fs()") replaced an occurrence of __get_user() with
get_kernel_nofault(), but inverted the sense of the conditional in the
process, resulting in no values to be printed at all.

I.e., every exception stack now looks like this:

Exception stack(0xc18d1fb0 to 0xc18d1ff8)
1fa0:                                     ???????? ???????? ???????? ????????
1fc0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ????????
1fe0: ???????? ???????? ???????? ???????? ???????? ????????

which is rather unhelpful.

Fixes: 344179f ("ARM: 9106/1: traps: use get_kernel_nofault instead of set_fs()")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

arch/arm/kernel/traps.c

@@ -136,7 +136,7 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
 		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
 			if (p >= bottom && p < top) {
 				unsigned long val;
-				if (get_kernel_nofault(val, (unsigned long *)p))
+				if (!get_kernel_nofault(val, (unsigned long *)p))
 					sprintf(str + i * 9, " %08lx", val);
 				else
 					sprintf(str + i * 9, " ????????");