powerpc: Use ALIGN instead of BLOCK

In the ld documentation under Builtin Functions:

  BLOCK(exp)

    This is a synonym for ALIGN, for compatibility with older linker scripts.

Clang's linker (lld) doesn't know about BLOCK so remove this use of
it.
Suggested-by: George Rimar <grimar@accesssoftek.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/vmlinux.lds.S

@@ -86,11 +86,11 @@ SECTIONS
 
 #ifdef CONFIG_PPC64
 	/*
-	 * BLOCK(0) overrides the default output section alignment because
+	 * ALIGN(0) overrides the default output section alignment because
 	 * this needs to start right after .head.text in order for fixed
 	 * section placement to work.
 	 */
-	.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
+	.text ALIGN(0) : AT(ADDR(.text) - LOAD_OFFSET) {
 #ifdef CONFIG_LD_HEAD_STUB_CATCH
 		KEEP(*(.linker_stub_catch));
 		. = . ;