nvptx: Remove newlib ELIX level 1 restriction

Such a hard-coded ELIX level restriction is only being applied for nvptx
newlib -- but we'd actually like higher levels' functions available there,
too.  (Users continue to be able to override this via newlib 'configure',
as for every other newlib target.)

This already enables GCC test cases that currently FAIL due to
'unresolved symbol strndup' ('gcc.dg/builtin-dynamic-object-size-0.c'), or
'unresolved symbol mempcpy' ('gcc.dg/torture/pr45636.c'), for example.

Co-authored-by: Andrew Stubbs <ams@codesourcery.com>

newlib/NEWS

@@ -13,6 +13,7 @@
 - use global stdio streams for all configurations
 - use global atexit data for all configurations
 - vectorized math routines added for amdgcn platform
+- nvptx: remove newlib ELIX level 1 restriction
 
 *** Major changes in newlib version 4.2.0:
 

newlib/configure.host

@@ -938,11 +938,6 @@ fi
 # Target-specific defaults
 case "${host_cpu}" in
   nvptx*)
-	if [ "x${newlib_elix_level}" = "x0" ]; then
-		newlib_elix_level=1;
-	elif [ "x${newlib_elix_level}" != "x1" ]; then
-		newlib_msg_warn="nvptx does not support elix level > 1";
-	fi
 	if [[ -z ${newlib_global_stdio_streams} ]]; then
 		newlib_global_stdio_streams="yes";
 	fi