clk: socfpga: fix iomem pointer cast on 64-bit

clk: socfpga: fix iomem pointer cast on 64-bit

Pointers should be cast with uintptr_t instead of integer.  This fixes
warning when compile testing on ARM64:

  drivers/clk/socfpga/clk-gate.c: In function ‘socfpga_clk_recalc_rate’:
  drivers/clk/socfpga/clk-gate.c:102:7: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

Fixes: b7cec13f082f ("clk: socfpga: Look for the GPIO_DB_CLK by its offset")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Link: https://lore.kernel.org/r/20210314110709.32599-1-krzysztof.kozlowski@canonical.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>