clk: socfpga: remove redundant assignment after a mask operation

The assignment operation after a & mask operation is redundant, the
variables being assigned are not used afterwards. Replace the &=
operator with just & operator.

Cleans up two clang-scan warnings:
drivers/clk/socfpga/clk-gate.c:37:10: warning: Although the value stored
to 'l4_src' is used in the enclosing expression, the value is never
actually read from 'l4_src' [deadcode.DeadStores]
                return l4_src &= 0x1;
                       ^         ~~~
drivers/clk/socfpga/clk-gate.c:46:10: warning: Although the value stored
to 'perpll_src' is used in the enclosing expression, the value is never
actually read from 'perpll_src' [deadcode.DeadStores]
                return perpll_src &= 0x3;

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20211230150321.167576-1-colin.i.king@gmail.com
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/socfpga/clk-gate.c

@@ -34,7 +34,7 @@ static u8 socfpga_clk_get_parent(struct clk_hw *hwclk)
 
 	if (streq(name, SOCFPGA_L4_MP_CLK)) {
 		l4_src = readl(clk_mgr_base_addr + CLKMGR_L4SRC);
-		return l4_src &= 0x1;
+		return l4_src & 0x1;
 	}
 	if (streq(name, SOCFPGA_L4_SP_CLK)) {
 		l4_src = readl(clk_mgr_base_addr + CLKMGR_L4SRC);
@@ -43,7 +43,7 @@ static u8 socfpga_clk_get_parent(struct clk_hw *hwclk)
 
 	perpll_src = readl(clk_mgr_base_addr + CLKMGR_PERPLL_SRC);
 	if (streq(name, SOCFPGA_MMC_CLK))
-		return perpll_src &= 0x3;
+		return perpll_src & 0x3;
 	if (streq(name, SOCFPGA_NAND_CLK) ||
 	    streq(name, SOCFPGA_NAND_X_CLK))
 		return (perpll_src >> 2) & 3;