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: 3c816d95 ("ARM: pxa: move clk register definitions to driver")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305111301.RAHohdob-lkp@intel.com/Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230511105845.299859-1-arnd@kernel.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/pxa/clk-pxa3xx.c

@@ -164,7 +164,7 @@ void pxa3xx_clk_update_accr(u32 disable, u32 enable, u32 xclkcfg, u32 mask)
 	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));