[arm][gas] Add support for Neoverse N1

This adds support for the Neoverse N1 CPU [1] to gas.
This was previously enabled under the Ares codename, which remains as
a valid option for -mcpu for compatibility reasons.

make check-gas passes on arm-none-eabi.

[1] https://community.arm.com/processors/b/blog/posts/arm-neoverse-n1-platform-accelerating-the-transformation-to-a-scalable-cloud-to-edge-infrastructure

2019-02-21  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

    * config/tc-arm.c (arm_cpus): Add neoverse-n1.
    * doc/c-arm.texi (-mcpu): Document neoverse-n1 value.

gas/ChangeLog

@@ -1,3 +1,8 @@
+2019-02-22  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/tc-arm.c (arm_cpus): Add neoverse-n1.
+	* doc/c-arm.texi (-mcpu): Document neoverse-n1 value.
+
 2019-02-22  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/tc-aarch64.c (aarch64_cpus): Add neoverse-e1.

gas/config/tc-arm.c

@@ -26264,7 +26264,9 @@ static const struct arm_cpu_option_table arm_cpus[] =
   ARM_CPU_OPT ("exynos-m1",	  "Samsung Exynos M1", ARM_ARCH_V8A,
 	       ARM_FEATURE_COPROC (CRC_EXT_ARMV8),
 	       FPU_ARCH_CRYPTO_NEON_VFP_ARMV8),
-
+  ARM_CPU_OPT ("neoverse-n1",    "Neoverse N1",	       ARM_ARCH_V8_2A,
+	       ARM_FEATURE_CORE_HIGH (ARM_EXT2_FP16_INST),
+	       FPU_ARCH_CRYPTO_NEON_VFP_ARMV8_DOTPROD),
   /* ??? XSCALE is really an architecture.  */
   ARM_CPU_OPT ("xscale",	  NULL,		       ARM_ARCH_XSCALE,
 	       ARM_ARCH_NONE,

gas/doc/c-arm.texi

@@ -147,6 +147,7 @@ recognized:
 @code{exynos-m1},
 @code{marvell-pj4},
 @code{marvell-whitney},
+@code{neoverse-n1},
 @code{xgene1},
 @code{xgene2},
 @code{ep9312} (ARM920 with Cirrus Maverick coprocessor),