Recognize 'powerpc' As an Alias for IH_ARCH_PPC

Add support for the recognition of 'powerpc' as an alias for the PowerPC
architecture type since Linux is already trending in that direction,
preferring 'powerpc' to 'ppc'.

Signed-off-by: Grant Erickson <gerickson@nuovations.com>

common/image.c

@@ -93,6 +93,7 @@ static table_entry_t uimage_arch[] = {
 	{	IH_ARCH_MIPS64,		"mips64",	"MIPS 64 Bit",	},
 	{	IH_ARCH_NIOS,		"nios",		"NIOS",		},
 	{	IH_ARCH_NIOS2,		"nios2",	"NIOS II",	},
+	{	IH_ARCH_PPC,		"powerpc",	"PowerPC",	},
 	{	IH_ARCH_PPC,		"ppc",		"PowerPC",	},
 	{	IH_ARCH_S390,		"s390",		"IBM S390",	},
 	{	IH_ARCH_SH,		"sh",		"SuperH",	},