hikey960: fix build issue for clang

plat/hisilicon/hikey960/include/plat_macros.S:19:55: error: unexpected token in
'.asciz' directive
 .asciz "gicd_ispendr regs (Offsets 0x200 - 0x278)\n" " Offset:\t\t\tvalue\n"
                                                      ^
Makefile:720: recipe for target 'build/hikey960/debug/bl1/cortex_a53.o' failed
make: *** [build/hikey960/debug/bl1/cortex_a53.o] Error 1

Merge the two lines into one.
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

plat/hisilicon/hikey960/include/plat_macros.S

@@ -16,8 +16,7 @@
 gicc_regs:
 	.asciz "gicc_hppir", "gicc_ahppir", "gicc_ctlr", ""
 gicd_pend_reg:
-	.asciz "gicd_ispendr regs (Offsets 0x200 - 0x278)\n"    \
-                " Offset:\t\t\tvalue\n"
+	.asciz "gicd_ispendr regs (Offsets 0x200 - 0x278)\n Offset:\t\t\tvalue\n"
 newline:
 	.asciz "\n"
 spacer: