drm/msm: Simplify NULL checking in msm_disp_state_dump_regs()

The msm_disp_state_dump_regs():

- Doesn't allocate if the caller already allocated. ...but there's one
  caller and it doesn't allocate so we don't need this check.
- Checks for allocation failure over and over even though it could
  just do it once right after the allocation.

Clean this up.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/619660/
Link: https://lore.kernel.org/r/20241014093605.3.I66049c2c17bd82767661f0ecd741b20453da02b2@changeid
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Author: dianders

drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c

@@ -25,24 +25,21 @@ static void msm_disp_state_dump_regs(u32 **reg, u32 aligned_len, void __iomem *b
 	addr = base_addr;
 	end_addr = base_addr + aligned_len;
 
-	if (!(*reg))
-		*reg = kvzalloc(len_padded, GFP_KERNEL);
-
-	if (*reg)
-		dump_addr = *reg;
+	*reg = kvzalloc(len_padded, GFP_KERNEL);
+	if (!*reg)
+		return;
 
+	dump_addr = *reg;
 	for (i = 0; i < num_rows; i++) {
 		x0 = (addr < end_addr) ? readl_relaxed(addr + 0x0) : 0;
 		x4 = (addr + 0x4 < end_addr) ? readl_relaxed(addr + 0x4) : 0;
 		x8 = (addr + 0x8 < end_addr) ? readl_relaxed(addr + 0x8) : 0;
 		xc = (addr + 0xc < end_addr) ? readl_relaxed(addr + 0xc) : 0;
 
-		if (dump_addr) {
-			dump_addr[i * 4] = x0;
-			dump_addr[i * 4 + 1] = x4;
-			dump_addr[i * 4 + 2] = x8;
-			dump_addr[i * 4 + 3] = xc;
-		}
+		dump_addr[i * 4] = x0;
+		dump_addr[i * 4 + 1] = x4;
+		dump_addr[i * 4 + 2] = x8;
+		dump_addr[i * 4 + 3] = xc;
 
 		addr += REG_DUMP_ALIGN;
 	}