powerpc: Override __ALIGN and __ALIGN_STR macros

In a subsequent patch, we would want to annotate powerpc assembly functions
with SYM_FUNC_START_LOCAL macro. This macro depends on __ALIGN macro.

The default expansion of __ALIGN macro is:
        #define __ALIGN      .align 4,0x90

So, override __ALIGN and __ALIGN_STR macros to use the same alignment as
that of the existing _GLOBAL macro. Also, do not pad with 0x90, because
repeated 0x90s are not a nop or trap on powerpc.
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-3-sv@linux.ibm.com

arch/powerpc/include/asm/linkage.h

@@ -4,6 +4,9 @@
 
 #include <asm/types.h>
 
+#define __ALIGN		.align 2
+#define __ALIGN_STR	".align 2"
+
 #ifdef CONFIG_PPC64_ELF_ABI_V1
 #define cond_syscall(x) \
 	asm ("\t.weak " #x "\n\t.set " #x ", sys_ni_syscall\n"		\