pinctrl: sprd: Use define directive for sprd_pinconf_params values

pinctrl: sprd: Use define directive for sprd_pinconf_params values

Clang warns when one enumerated type is implicitly converted to another:

drivers/pinctrl/sprd/pinctrl-sprd.c:845:19: warning: implicit conversion
from enumeration type 'enum sprd_pinconf_params' to different
enumeration type 'enum pin_config_param' [-Wenum-conversion]
        {"sprd,control", SPRD_PIN_CONFIG_CONTROL, 0},
        ~                ^~~~~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/sprd/pinctrl-sprd.c:846:22: warning: implicit conversion
from enumeration type 'enum sprd_pinconf_params' to different
enumeration type 'enum pin_config_param' [-Wenum-conversion]
        {"sprd,sleep-mode", SPRD_PIN_CONFIG_SLEEP_MODE, 0},
        ~                   ^~~~~~~~~~~~~~~~~~~~~~~~~~

It is expected that pinctrl drivers can extend pin_config_param because
of the gap between PIN_CONFIG_END and PIN_CONFIG_MAX so this conversion
isn't an issue. Most drivers that take advantage of this define the
PIN_CONFIG variables as constants, rather than enumerated values. Do the
same thing here so that Clang no longer warns.

Link: https://github.com/ClangBuiltLinux/linux/issues/138
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>