ARM: 5883/1: Revert "disable NX support for OABI-supporting kernels"

This reverts commit 14f0aa35.

That commit was needed earlier because system call restarting for
OABI (compat) required an executable stack and thus had problems
with NX.  Since ab72b007 ("ARM: Fix signal restart issues
with NX and OABI compat") has reworked the code to not require an
executable stack anymore, we can re-enable NX support for kernels
with OABI (compat) support.
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/elf.c

@@ -78,15 +78,6 @@ int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack)
 		return 1;
 	if (cpu_architecture() < CPU_ARCH_ARMv6)
 		return 1;
-#if !defined(CONFIG_AEABI) || defined(CONFIG_OABI_COMPAT)
-	/*
-	 * If we have support for OABI programs, we can never allow NX
-	 * support - our signal syscall restart mechanism relies upon
-	 * being able to execute code placed on the user stack.
-	 */
-	return 1;
-#else
 	return 0;
-#endif
 }
 EXPORT_SYMBOL(arm_elf_read_implies_exec);