refactor(aarch64): rename do_panic and el3_panic

Current panic call invokes do_panic which calls el3_panic, but now panic
handles only panic from EL3 anid clear separation to use lower_el_panic()
which handles panic from lower ELs.

So now we can remove do_panic and just call el3_panic for all panics.

Change-Id: I739c69271b9fb15c1176050877a9b0c0394dc739
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst
index 80b72e5..98568cd 100644
--- a/docs/getting_started/porting-guide.rst
+++ b/docs/getting_started/porting-guide.rst
@@ -3205,8 +3205,8 @@
 Common helper functions
 -----------------------
 
-Function : do_panic()
-~~~~~~~~~~~~~~~~~~~~~
+Function : el3_panic()
+~~~~~~~~~~~~~~~~~~~~~~
 
 ::
 
@@ -3214,9 +3214,8 @@
     Return   : void
 
 This API is called from assembly files when encountering a critical failure that
-cannot be recovered from. It also invokes elx_panic() which allows to report a
-crash from lower exception level. This function assumes that it is invoked from
-a C runtime environment i.e. valid stack exists. This call **must not** return.
+cannot be recovered from. This function assumes that it is invoked from a C
+runtime environment i.e. valid stack exists. This call **must not** return.
 
 Function : panic()
 ~~~~~~~~~~~~~~~~~~
@@ -3228,7 +3227,7 @@
 
 This API called from C files when encountering a critical failure that cannot
 be recovered from. This function in turn prints backtrace (if enabled) and calls
-do_panic(). This call **must not** return.
+el3_panic(). This call **must not** return.
 
 Crash Reporting mechanism (in BL31)
 -----------------------------------