vita: reserve 64kb for sce data (#19514)

Makefile.vita

@@ -13,6 +13,7 @@ PC_DEVELOPMENT_UDP_PORT	   =
 
 OBJ :=
 
+SCE_HEADROOM ?= 0x10000
 SCE_LIBC_SIZE := 4194304
 DEFINES := -DHAVE_ONLINE_UPDATER -DHAVE_UPDATE_ASSETS
 INCDIRS :=
@@ -148,6 +149,10 @@ endif
 ASFLAGS := $(CFLAGS)
 LDFLAGS := -Wl,-q,--pic-veneer
 
+ifneq ($(SCE_HEADROOM),0)
+LDFLAGS += -Wl,--defsym=__sce_headroom=$(SCE_HEADROOM)
+endif
+
 CFLAGS += -Wall
 CFLAGS += -DRARCH_INTERNAL -DHAVE_SCREENSHOTS -DRARCH_CONSOLE
 CFLAGS += -DHAVE_DSP_FILTER