clk: pxa: fix NULL pointer dereference in pxa3xx_clk_update_accr

sparse points out an embarrasing bug in an older patch of mine,
which uses the register offset instead of an __iomem pointer:

drivers/clk/pxa/clk-pxa3xx.c:167:9: sparse: sparse: Using plain integer as NULL pointer

Unlike sparse, gcc and clang ignore this bug and fail to warn
because a literal '0' is considered a valid representation of
a NULL pointer.

Fixes: 3c816d950a49 ("ARM: pxa: move clk register definitions to driver")
Cc: [e-mail]
Reported-by: kernel test robot <[e-mail]>
Link: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Arnd Bergmann <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/pxa/clk-pxa3xx.c

···
 	accr &= ~disable;
 	accr |= enable;
 
-	writel(accr, ACCR);
+	writel(accr, clk_regs + ACCR);
 	if (xclkcfg)
 		__asm__("mcr p14, 0, %0, c6, c0, 0\n" : : "r"(xclkcfg));