Modify perdev_minors path to reflect loadable MMC module

/sys/module path changes in case of loadable MMC module.

Test: End to end sdcard verification on 5.4 kernel where MMC modules
      are loadable modules.

Bug: 153595127
CRs-Fixed: 2653422
Change-Id: I96cfb614f94178fd559e20c06cced87402312582
diff --git a/model/Disk.cpp b/model/Disk.cpp
index a4324db..ada1226 100644
--- a/model/Disk.cpp
+++ b/model/Disk.cpp
@@ -53,7 +53,7 @@
 
 static const char* kSysfsLoopMaxMinors = "/sys/module/loop/parameters/max_part";
 static const char* kSysfsMmcMaxMinorsDeprecated = "/sys/module/mmcblk/parameters/perdev_minors";
-static const char* kSysfsMmcMaxMinors = "/sys/module/mmc_block/parameters/perdev_minors";
+static const char* kSysfsMmcMaxMinors = "/sys/module/mmc_block/parameters/mmcblk.perdev_minors";
 
 static const unsigned int kMajorBlockLoop = 7;
 static const unsigned int kMajorBlockScsiA = 8;