powerpc: Rename "notes" PT_NOTE to "note"

The Program Header identifiers are internal to the linker scripts. In
preparation for moving the NOTES segment declaration into RO_DATA,
standardize the identifier for the PT_NOTE entry to "note" as used by
all other architectures that emit PT_NOTE.

Note that there was discussion about changing all architectures to use
"notes" instead, but I prefer to avoid that at this time. Changing only
powerpc is the smallest change to standardize the entire kernel. And
while this standardization does use singular "note" for a section that
has more than one note in it, this is just an internal identifier. It
matches the ELF "PT_NOTE", and is 4 characters (like "text", and "data")
for pretty alignment. The more exposed macro, "NOTES", use the more
sensible plural wording.

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-ml <x86@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-2-keescook@chromium.org

arch/powerpc/kernel/vmlinux.lds.S

@@ -19,7 +19,7 @@ ENTRY(_stext)
 
 PHDRS {
 	kernel PT_LOAD FLAGS(7); /* RWX */
-	notes PT_NOTE FLAGS(0);
+	note PT_NOTE FLAGS(0);
 	dummy PT_NOTE FLAGS(0);
 
 	/* binutils < 2.18 has a bug that makes it misbehave when taking an
@@ -177,7 +177,7 @@ SECTIONS
 #endif
 	EXCEPTION_TABLE(0)
 
-	NOTES :kernel :notes
+	NOTES :kernel :note
 
 	/* The dummy segment contents for the bug workaround mentioned above
 	   near PHDRS.  */