[PARISC] Add is_compat_task() helper

... And convert signal.c and ptrace.c to use it instead of open
coded equivalents.

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 413292f..3f28de9 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -91,7 +91,7 @@
 		int copied;
 
 #ifdef __LP64__
-		if (personality(child->personality) == PER_LINUX32) {
+		if (__is_compat_task(child)) {
 			unsigned int tmp;
 
 			addr &= 0xffffffffL;
@@ -123,7 +123,7 @@
 	case PTRACE_POKEDATA:
 		ret = 0;
 #ifdef __LP64__
-		if (personality(child->personality) == PER_LINUX32) {
+		if (__is_compat_task(child)) {
 			unsigned int tmp = (unsigned int)data;
 			DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n",
 				request == PTRACE_POKETEXT ? "TEXT" : "DATA",
@@ -146,7 +146,7 @@
 	case PTRACE_PEEKUSR: {
 		ret = -EIO;
 #ifdef __LP64__
-		if (personality(child->personality) == PER_LINUX32) {
+		if (__is_compat_task(child)) {
 			unsigned int tmp;
 
 			if (addr & (sizeof(int)-1))
@@ -205,7 +205,7 @@
 			goto out_tsk;
 		}
 #ifdef __LP64__
-		if (personality(child->personality) == PER_LINUX32) {
+		if (__is_compat_task(child)) {
 			if (addr & (sizeof(int)-1))
 				goto out_tsk;
 			if ((addr = translate_usr_offset(addr)) < 0)