mmc: omap_hsmmc: Simplify bool comparison and conversion

Fix the following coccicheck warning:
./drivers/mmc/host/omap_hsmmc.c:297:6-25: WARNING: Comparison of 0/1 to
bool variable

According to the context, vqmmc_enabled is more suitable for bool type.

Reported-by: Abaci <Robot&lt;abaci@linux.alibaba.com>
Signed-off-by: Yang Li <abaci-bugfix@linux.alibaba.com>
Link: https://lore.kernel.org/r/1610704281-11036-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>