Tegra186: modify the return type for `plat_get_syscnt_freq()`

Commit c073fda1c6 upstream changed the
return type for `plat_get_syscnt_freq()` from uint64_t to unsigned
long long.

This patch modifies the return type for the Tegra186 platform.

Change-Id: Ic9e5c364b90972265576e271582a4347e5eaa6eb
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

plat/nvidia/tegra/soc/t186/plat_setup.c

@@ -113,7 +113,7 @@ const mmap_region_t *plat_get_mmio_map(void)
 /*******************************************************************************
  * Handler to get the System Counter Frequency
  ******************************************************************************/
-unsigned int plat_get_syscnt_freq2(void)
+unsigned long long plat_get_syscnt_freq(void)
 {
 	return 31250000;
 }