flash_map: Increase minimum supported write align via flash_area_align

Signed-off-by: Gustavo Henrique Nihei <gustavo.nihei@espressif.com>
diff --git a/boot/bootutil/src/loader.c b/boot/bootutil/src/loader.c
index 10bd5c6..6f6343c 100644
--- a/boot/bootutil/src/loader.c
+++ b/boot/bootutil/src/loader.c
@@ -426,7 +426,7 @@
     int area_id;
     int rc = 0;
     uint8_t buf[BOOT_MAX_ALIGN];
-    uint8_t align;
+    uint32_t align;
     uint8_t erased_val;
 
     /* NOTE: The first sector copied (that is the last sector on slot) contains