clk: clk-xgene: simplify if-if to if-else

Replace `if (!pclk->param.csr_reg)` with `else` for simplification
and add curly brackets according to the kernel coding style:

"Do not unnecessarily use braces where a single statement will do."

...

"This does not apply if only one branch of a conditional statement is
a single statement; in the latter case use braces in both branches"

Please refer to:
https://www.kernel.org/doc/html/v5.17-rc8/process/coding-style.html

Signed-off-by: Yihao Han <hanyihao@vivo.com>
Link: https://lore.kernel.org/r/20220408130617.14963-1-hanyihao@vivo.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk-xgene.c

@@ -522,10 +522,10 @@ static int xgene_clk_is_enabled(struct clk_hw *hw)
 		pr_debug("%s clock is %s\n", clk_hw_get_name(hw),
 			data & pclk->param.reg_clk_mask ? "enabled" :
 							"disabled");
+	} else {
+		return 1;
 	}
 
-	if (!pclk->param.csr_reg)
-		return 1;
 	return data & pclk->param.reg_clk_mask ? 1 : 0;
 }