gpio: add missing MODULE_DESCRIPTION() macros

On x86, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpio/gpio-gw-pld.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpio/gpio-mc33880.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpio/gpio-pcf857x.o

Add the missing invocations of the MODULE_DESCRIPTION() macro,
including the one missing in gpio-pl061.c, which is not built for x86.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240606-md-drivers-gpio-v1-1-cb42d240ca5c@quicinc.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: Jeff Johnson

drivers/gpio/gpio-gw-pld.c

@@ -130,5 +130,6 @@ static struct i2c_driver gw_pld_driver = {
 };
 module_i2c_driver(gw_pld_driver);
 
+MODULE_DESCRIPTION("Gateworks I2C PLD GPIO expander");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

drivers/gpio/gpio-mc33880.c

@@ -168,5 +168,6 @@ static void __exit mc33880_exit(void)
 module_exit(mc33880_exit);
 
 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
+MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver");
 MODULE_LICENSE("GPL v2");
 

drivers/gpio/gpio-pcf857x.c

@@ -438,5 +438,6 @@ static void __exit pcf857x_exit(void)
 }
 module_exit(pcf857x_exit);
 
+MODULE_DESCRIPTION("Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("David Brownell");

drivers/gpio/gpio-pl061.c

@@ -438,4 +438,5 @@ static struct amba_driver pl061_gpio_driver = {
 };
 module_amba_driver(pl061_gpio_driver);
 
+MODULE_DESCRIPTION("Driver for the ARM PrimeCell(tm) General Purpose Input/Output (PL061)");
 MODULE_LICENSE("GPL v2");