clk: samsung: Fix UBSAN panic in samsung_clk_init()

clk: samsung: Fix UBSAN panic in samsung_clk_init()

With UBSAN_ARRAY_BOUNDS=y, I'm hitting the below panic due to
dereferencing `ctx->clk_data.hws` before setting
`ctx->clk_data.num = nr_clks`. Move that up to fix the crash.

  UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP
  <snip>
  Call trace:
   samsung_clk_init+0x110/0x124 (P)
   samsung_clk_init+0x48/0x124 (L)
   samsung_cmu_register_one+0x3c/0xa0
   exynos_arm64_register_cmu+0x54/0x64
   __gs101_cmu_top_of_clk_init_declare+0x28/0x60
   ...

Fixes: e620a1e061c4 ("drivers/clk: convert VL struct to struct_size")
Signed-off-by: Will McVicker <willmcvicker@google.com>
Link: https://lore.kernel.org/r/20250212183253.509771-1-willmcvicker@google.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>