timer: bcmbca: use arm global timer for bcm63138 SoC

As STI timer is renamed to ARM A9 global timer, change BCM63138 to use
the new global timer config symbol name.

This patch applies on top of the my previous patch [1].

[1]: https://lists.denx.de/pipermail/u-boot/2022-August/491060.html

Signed-off-by: William Zhang <william.zhang@broadcom.com>
diff --git a/arch/arm/mach-bcmbca/Kconfig b/arch/arm/mach-bcmbca/Kconfig
index 27b243c..62b3716 100644
--- a/arch/arm/mach-bcmbca/Kconfig
+++ b/arch/arm/mach-bcmbca/Kconfig
@@ -29,7 +29,7 @@
 config BCM63138
 	bool "Support for Broadcom 63138 Family"
 	select TIMER
-	select STI_TIMER
+	select ARM_GLOBAL_TIMER
 	select CPU_V7A
 	select DM_SERIAL
 	select BCM6345_SERIAL