mmc: sdhci-brcmstb: Re-organize flags

Re-organize the flags by basing the bit names on the flag that they
apply to. Also change the "flags" member in the "brcmstb_match_priv"
struct to const.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20220427180853.35970-2-kdasu.kdev@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>