perf(cpus): inline the reset function

Similar to the cpu_rev_var and cpu_ger_rev_var functions, inline the
call_reset_handler handler. This way we skip the costly branch at no
extra cost as this is the only place where this is called.

While we're at it, drop the options for CPU_NO_RESET_FUNC. The only cpus
that need that are virtual cpus which can spare the tiny bit of
performance lost. The rest are real cores which can save on the check
for zero.

Now is a good time to put the assert for a missing cpu in the
get_cpu_ops_ptr function so that it's a bit better encapsulated.

Change-Id: Ia7c3dcd13b75e5d7c8bafad4698994ea65f42406
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/include/lib/cpus/aarch32/cpu_macros.S b/include/lib/cpus/aarch32/cpu_macros.S
index cfa5831..a878a5f 100644
--- a/include/lib/cpus/aarch32/cpu_macros.S
+++ b/include/lib/cpus/aarch32/cpu_macros.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2024, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -48,8 +48,7 @@
 	 * _midr:
 	 *	Numeric value expected to read from CPU's MIDR
 	 * _resetfunc:
-	 *	Reset function for the CPU. If there's no CPU reset function,
-	 *	specify CPU_NO_RESET_FUNC
+	 *	Reset function for the CPU
 	 * _power_down_ops:
 	 *	Comma-separated list of functions to perform power-down
 	 *	operatios on the CPU. At least one, and up to
diff --git a/include/lib/cpus/aarch64/cpu_macros.S b/include/lib/cpus/aarch64/cpu_macros.S
index 17592d3..c8f4bde 100644
--- a/include/lib/cpus/aarch64/cpu_macros.S
+++ b/include/lib/cpus/aarch64/cpu_macros.S
@@ -49,8 +49,7 @@
 	 * _midr:
 	 *	Numeric value expected to read from CPU's MIDR
 	 * _resetfunc:
-	 *	Reset function for the CPU. If there's no CPU reset function,
-	 *	specify CPU_NO_RESET_FUNC
+	 *	Reset function for the CPU.
 	 * _extra1:
 	 *	This is a placeholder for future per CPU operations.  Currently,
 	 *	some CPUs use this entry to set a test function to determine if
diff --git a/include/lib/cpus/cpu_ops.h b/include/lib/cpus/cpu_ops.h
index c1bdf8d..0b08919 100644
--- a/include/lib/cpus/cpu_ops.h
+++ b/include/lib/cpus/cpu_ops.h
@@ -21,8 +21,6 @@
 
 /* The number of CPU operations allowed */
 #define CPU_MAX_PWR_DWN_OPS		2
-/* Special constant to specify that CPU has no reset function */
-#define CPU_NO_RESET_FUNC		0
 
 #if __aarch64__
 #define CPU_NO_EXTRA1_FUNC		0