nxp_adsp: linker: Rename text area variables

Use Zephyr's convention for text region start and end.

Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
diff --git a/soc/xtensa/nxp_adsp/imx8/linker.ld b/soc/xtensa/nxp_adsp/imx8/linker.ld
index 7e5829c..52d3a46 100644
--- a/soc/xtensa/nxp_adsp/imx8/linker.ld
+++ b/soc/xtensa/nxp_adsp/imx8/linker.ld
@@ -346,7 +346,7 @@
   .text : ALIGN(4)
   {
     _stext = .;
-    _text_start = ABSOLUTE(.);
+    __text_region_start = ABSOLUTE(.);
     KEEP (*(.ResetVector.text))
     *(.ResetVector.literal)
     *(.entry.text)
@@ -356,7 +356,7 @@
     *(.fini.literal)
     KEEP(*(.fini))
     *(.gnu.version)
-    _text_end = ABSOLUTE(.);
+    __text_region_end = ABSOLUTE(.);
     _etext = .;
   } >sdram0 :sdram0_phdr
 
diff --git a/soc/xtensa/nxp_adsp/imx8m/linker.ld b/soc/xtensa/nxp_adsp/imx8m/linker.ld
index 235e5a6..7df1964 100644
--- a/soc/xtensa/nxp_adsp/imx8m/linker.ld
+++ b/soc/xtensa/nxp_adsp/imx8m/linker.ld
@@ -352,7 +352,7 @@
   .text : ALIGN(4)
   {
     _stext = .;
-    _text_start = ABSOLUTE(.);
+    __text_region_start = ABSOLUTE(.);
     KEEP (*(.ResetVector.text))
     *(.ResetVector.literal)
     *(.entry.text)
@@ -362,7 +362,7 @@
     *(.fini.literal)
     KEEP(*(.fini))
     *(.gnu.version)
-    _text_end = ABSOLUTE(.);
+    __text_region_end = ABSOLUTE(.);
     _etext = .;
   } >sdram0 :sdram0_phdr
 
diff --git a/soc/xtensa/nxp_adsp/rt5xx/linker.ld b/soc/xtensa/nxp_adsp/rt5xx/linker.ld
index 582c4a7..adc8b87 100644
--- a/soc/xtensa/nxp_adsp/rt5xx/linker.ld
+++ b/soc/xtensa/nxp_adsp/rt5xx/linker.ld
@@ -307,7 +307,7 @@
   .text : ALIGN(4)
   {
     _stext = .;
-    _text_start = ABSOLUTE(.);
+    __text_region_start = ABSOLUTE(.);
     KEEP (*(.ResetVector.text))
     *(.ResetVector.literal)
     *(.entry.text)
@@ -317,7 +317,7 @@
     *(.fini.literal)
     KEEP(*(.fini))
     *(.gnu.version)
-    _text_end = ABSOLUTE(.);
+    __text_region_end = ABSOLUTE(.);
     _etext = .;
   } >iram_text_start :iram_text_start_phdr