powerpc: Rename PT_LOAD identifier "kernel" to "text"

In preparation for moving NOTES into RO_DATA, rename the linker script
internal identifier for the PT_LOAD Program Header from "kernel" to
"text" to match other architectures.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Will Deacon <will@kernel.org>
Cc: x86@kernel.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-4-keescook@chromium.org

arch/powerpc/kernel/vmlinux.lds.S

@@ -18,7 +18,7 @@
 ENTRY(_stext)
 
 PHDRS {
-	kernel PT_LOAD FLAGS(7); /* RWX */
+	text PT_LOAD FLAGS(7); /* RWX */
 	note PT_NOTE FLAGS(0);
 }
 
@@ -63,7 +63,7 @@ SECTIONS
 #else /* !CONFIG_PPC64 */
 		HEAD_TEXT
 #endif
-	} :kernel
+	} :text
 
 	__head_end = .;
 
@@ -112,7 +112,7 @@ SECTIONS
 		__got2_end = .;
 #endif /* CONFIG_PPC32 */
 
-	} :kernel
+	} :text
 
 	. = ALIGN(ETEXT_ALIGN_SIZE);
 	_etext = .;
@@ -163,9 +163,9 @@ SECTIONS
 #endif
 	EXCEPTION_TABLE(0)
 
-	NOTES :kernel :note
+	NOTES :text :note
 	/* Restore program header away from PT_NOTE. */
-	.dummy : { *(.dummy) } :kernel
+	.dummy : { *(.dummy) } :text
 
 /*
  * Init sections discarded at runtime
@@ -180,7 +180,7 @@ SECTIONS
 #ifdef CONFIG_PPC64
 		*(.tramp.ftrace.init);
 #endif
-	} :kernel
+	} :text
 
 	/* .exit.text is discarded at runtime, not link time,
 	 * to deal with references from __bug_table